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First & Second Stages

First & Second Stages

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Buy individual scuba regulator first stages and second stages in Canada — standalone components for divers building a custom regulator configuration, upgrading an existing setup, or adding a backup regulator to their kit. First stages available in yoke and DIN configurations, balanced piston and balanced diaphragm designs, and environmentally sealed models for cold water diving. Second stages include primary and backup (octopus) options from Scubapro, Cressi, and Scuba Force. Looking for a complete ready-to-dive system? See our regulator packages. .
Tips on choosing the best regulator
  • Scubapro R105 Octopus Regulator Scubapro R105 Octopus Regulator - with silicone mouthpiece
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    Scubapro R105 Octopus Regulator

    Scubapro

    $332.99
    The Scubapro R105 scuba diving second stage octopus is pre-tuned to the optimum inhalation volume for safe and uncomplicated use. Simple construction yet very reliable. Features: Downstream...
    5071
    $332.99
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  • Scubapro MK25 EVO / S600 Regulator Set
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    Scubapro MK25 EVO / S600 Regulator Set

    Scubapro

    $1,589.99
    This regulator set is built to withstand cold diving conditions. The first stage features a fifth low pressure port with swivel, allowing for a variety of gear configurations. The second stage is...
    3018
    $1,589.99
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  • Scubapro MK25 EVO / A700 Regulator Set
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    Scubapro MK25 EVO / A700 Regulator Set

    Scubapro

    $1,879.99
    This regulator set is built to withstand cold diving conditions. It features a fifth low pressure port and swivel to assist with hose routing for technical and sidemount configurations.  First...
    2792
    $1,879.99
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  • Scubapro MK11 EVO / C370 Regulator Set Scubapro MK11 EVO / C370 Regulator
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    Scubapro MK11 EVO / C370 Regulator Set

    Scubapro

    $1,019.99
    This regulator set is a good lightweight, mid-range system that offers smooth breathing in all conditions. Best suited for warm water scuba diving. Chrome-plated brass body is specially designed to...
    5120
    $1,019.99
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  • Cressi Octopus Compact
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    Cressi Octopus Compact

    Cressi

    $229.99
    The Cressi Compact Octopus is a featherweight second stage built with lightweight techno-polymers to reduce jaw fatigue. Geared for warm water, this is the perfect backup regulator for the traveling...
    4919
    $229.99
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  • MK25 / G260 Regulator Set
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    Scubapro MK25 EVO / G260 Regulator Set

    Scubapro

    $1,519.99
    This regulator set is built to withstand cold diving conditions. The first stage features a fifth low pressure port with swivel and the second stage features left or right hand hose configuration,...
    3636
    $1,519.99
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  • Scubapro MK19 EVO / G260 Regulator Set Scubapro MK19 EVO first stage
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    Scubapro MK19 EVO / G260 Regulator Set

    Scubapro

    $1,519.99
    This regulator set is ideal for every condition from recreational to tech, cold to warm temperatures, clear water to muddy, silty or rusty water. The first stage is completely sealed ensuring no...
    4631
    $1,519.99
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  • On Sale
    MK2 First Stage with R195 Second Stage
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    Scubapro MK2 EVO / R195 Set

    Scubapro

    $599.49
    $719.99
    The MK2 regulator paired with the R195 second stage is perfect to use with a pony bottle for a backup air source. MK2 First Stage Features: Classic downstream piston design features a...
    3943
    $599.49
    $719.99
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  • On Sale
    Aropec RG-1002 Zenith Pony Regulator Set
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    Aropec 1002 DIN / Zenith Pony Regulator Set

    Aropec

    $375.49
    $499.99
    Reliable pony bottle setup to use as a backup air supply or deco stage bottle. The Aropec RG-1002 Zenith package is ready for cold water diving including ice diving. Our local tech divers have relied...
    5248
    $375.49
    $499.99
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  • Cressi MC9 / Compact Regulator Set
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    Cressi MC9 / Compact Regulator Set

    Cressi

    $649.99
    The Cressi MC9 / Compact regulator set is perfect for beginners and warm water travelers. It's compact and lightweight while maintaining high standards of the warm water scuba diver...
    4921
    $649.99
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  • STAFF PICK
    Scubapro MK17 EVO2 / G260 Regulator Set
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    Scubapro MK17 EVO2 / G260 Regulator Set

    Scubapro

    $1,319.99
    This regulator set is great for both cold and warm water diving. With the ability to switch the second stage between right or left hand configuration, it is a popular system for tech divers and cave...
    5223
    $1,319.99
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  • Scubapro MK19 EVO / A700 Regulator Set
    Add to Cart

    Scubapro MK19 EVO / A700 Regulator Set

    Scubapro

    $1,879.99
    This regulator set is ideal for every condition from recreational to tech, cold to warm temperatures, clear water to muddy, silty or rusty water. The first stage is completely sealed ensuring no...
    4760
    $1,879.99
    Add to Cart
  • Scubapro MK19 EVO DIN First Stage
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    Scubapro MK19 EVO DIN First Stage

    Scubapro

    $749.99
    This first stage DIN scuba regulator is ideal for every condition from recreational to tech, cold to warm temperatures, clear water to muddy, silty or rusty water. The first stage is completely...
    5344
    $749.99
    Add to Cart
  • Cressi MG Balanced Octopus
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    Cressi MG Balanced Octopus

    Cressi

    $369.95
    The Cressi Octopus MG is a high quality backup regulator for scuba diving in warm and cold water. Features: Pneumatically balanced valve with elliptical membrane diaphragm & low-friciton...
    4918
    $369.95
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  • Scuba Force Black Devil SM First Stage
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    Scuba Force Black Devil SM First Stage

    Scuba Force

    $599.99
    The Black Devil first stage is an environmentally sealed diaphragm style regulator. Great for reliable performance at any depth and any temperature.  Features: Made of corrosion-resistant brass,...
    4795
    $599.99
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  • TOP SELLER
    Scubapro MK19 EVO DIN / G260 Regulator Set
    Add to Cart

    Scubapro MK19 EVO DIN / G260 Regulator Set

    Scubapro

    $1,519.99
    This DIN scuba regulator set is ideal for every condition from recreational to tech, cold to warm temperatures, clear water to muddy, silty or rusty water. The first stage is completely sealed...
    5345
    $1,519.99
    Add to Cart

What to know about first and second stage regulators

Downstream vs. upstream second stage valves
A downstream valve opens in the same direction as airflow — if the first stage over-pressurizes, the downstream second stage opens automatically, resulting in a free-flow. This is the preferred design for recreational diving because a free-flow is manageable at the surface. An upstream valve opens against the airflow — if the first stage over-pressurizes, the valve can jam closed, cutting off the air supply. Upstream valves are used in specific technical configurations but are not recommended for recreational diving. All primary and backup second stages we carry for recreational use are downstream valve designs.

LP port count — planning your hose configuration
Most first stages have four low pressure ports and one or two high pressure ports. Your low pressure ports need to accommodate your primary second stage, backup second stage, BCD power inflator hose, and drysuit inflator hose if applicable — that's up to four hoses from low pressure ports alone. If you run a drysuit, a sidemount configuration, or a redundant computer transmitter, confirm your chosen first stage has enough ports before purchasing. The Scubapro MK25 EVO adds a fifth low pressure port with swivel, specifically for divers who need additional hose routing flexibility.

Primary vs. backup second stage — the difference matters
A primary second stage is optimized for breathing comfort — adjustable inhalation effort, dive/pre-dive lever, and high-performance airflow. A backup second stage (octopus) is designed for reliability and simplicity — typically non-adjustable, brightly colored (yellow is standard) for easy identification in an emergency, and built on a downstream valve design that defaults to a free-flow rather than a blocked valve if something fails. Backup second stages are mounted on longer hoses — typically 36 inches — so a buddy in distress can take it without pulling you toward them.

DIN conversion and adapter options
If you own a yoke first stage and need to dive on a DIN tank, or vice versa, adapters allow conversion without purchasing a new regulator. The DIN to Yoke Spin-On Adapter fits any DIN first stage and allows connection to a standard yoke/K-valve tank. The Scubapro DIN Conversion Kit converts compatible Scubapro yoke first stages to DIN permanently. If you travel between North America and Europe regularly, carrying a DIN to yoke adapter is simpler than owning two regulators.

Frequently asked questions

Can I mix first and second stage brands?

Generally yes — scuba regulator hoses use standardized thread fittings, so a Scubapro first stage can be connected to a Cressi second stage using a standard hose. However, for warranty purposes, most manufacturers prefer their components to be serviced and used together. Performance matching also matters — pairing a high-performance first stage with a basic backup second stage is common and works well. If you are unsure whether specific components will work together, contact us before ordering.

What does the dive/pre-dive lever on a second stage do?

The dive/pre-dive lever adjusts the cracking pressure of the second stage — in pre-dive position, the regulator requires a slightly harder inhale to open, which reduces the likelihood of free-flowing at the surface when the regulator is out of your mouth and exposed to splashing or wave action. In dive mode, the cracking pressure drops to the minimum for easiest underwater breathing. Always switch to dive mode before putting the regulator in your mouth underwater. Some regulators call this lever by different names — Venturi control, VAD (Venturi Adjustment Dial), or IVA (Inline Valve Adjuster) — but the function is the same.

What is the yellow hose on a backup regulator for?

Yellow is the internationally recognized color for a backup second stage (octopus). In an out-of-air emergency, a dive buddy in distress needs to locate your backup regulator quickly and under stress. The bright yellow hose and second stage make it immediately visible even in reduced visibility conditions. Your backup regulator should be mounted in the triangle formed by your chin, navel, and the sides of your chest — the standard "golden triangle" placement taught in open water certification. We carry yellow octopus hoses in 36-inch length as a replacement or upgrade for any backup regulator setup.

What is the difference between the first stage and second stage scuba regulator?

A scuba regulator has two main parts that work together to deliver breathable air underwater, the first stage and second stage. The first stage attaches directly to your scuba tank valve. Its job is to reduce the high-pressure air from the tank to an intermediate pressure that can be safely delivered through the regulator hoses. The second stage is the part you breathe from. When you inhale, it further reduces the air pressure to match the surrounding water pressure, delivering air comfortably and on demand. In simple terms, the first stage reduces tank pressure, while the second stage delivers air to the diver at a breathable pressure. Both are essential components of a safe and reliable scuba diving regulator system.