Mares Scuba Diving Mares Scuba Diving First Stage R2S
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Mares Scuba Diving Mares Scuba Diving First Stage R2S is backordered and will ship as soon as it is back in stock.
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Product Information
The Mares R2S First Stage is a piston-controlled scuba regulator first stage built for simple, reliable performance and easy maintenance, available in an INT connection configuration (MPN 416232INT).
Who it is for
This first stage suits divers who want a straightforward, low-maintenance regulator first stage for their primary life-support gear. With four low-pressure ports and one high-pressure port, it accommodates a primary second stage, octopus, inflator hose, drysuit hose, and a gauge or transmitter.
Key details
- Piston-controlled mechanism with a simple, robust design; Mares describes the 2S as simple and reliable for any use.
- Weighs 608 g (21.4 oz) in INT configuration; the DIN configuration weighs 432 g (15.2 oz)
- Four low-pressure ports, 3/8 in UNF
- One high-pressure port, 7/16 in UNF
- INT connection on this listing's configuration (416232INT)
- Straightforward to clean and service, per Mares
Compatibility and sizing
This listing is the INT connection version of the R2S first stage. Mares also publishes a DIN/INT NX connection option for this same model; confirm which connection your tank valve requires before ordering.
DiveCatalog.com is an authorized Mares dealer and a dive shop in Irvine, California, serving divers since 2003. Call 888-701-4017 or chat with us if you have questions about fit, connection type, or compatibility with the rest of your regulator setup.
- Piston-controlled design. Simple, robust mechanism for reliable performance.
- Compact and light. Weighs 432 g in the DIN configuration; 608 g in the INT configuration.
- Four low-pressure ports. Accommodates primary, octopus, inflator, and drysuit hoses.
- One high-pressure port. Fits a gauge or transmitter.
- INT connection. This listing (MPN 416232INT) is the INT connection configuration.
- Easy to service. Mares says the 2S is renowned for its ease of maintenance.
| Brand | Mares |
| Model | R2S (2S First Stage) |
| Product Type | First stage |
| Technology | Piston |
| Connection | INT (this listing, MPN 416232INT) |
| HP Ports | 1 (7/16 in UNF) |
| LP Ports | 4 (3/8 in UNF) |
| Weight (INT) | 608 g / 21.4 oz |
| Weight (DIN) | 432 g / 15.2 oz |
⚠️ WARNING: This product contains chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm. For more information, visit www.P65Warnings.ca.gov.
Frequently Asked Questions
How often does a scuba regulator need servicing?
Follow the interval in your regulator's manual, since manufacturers commonly specify an annual inspection or a set number of dives and many warranties depend on it. A regulator is life-support equipment, so service belongs with a factory-trained technician rather than being attempted at home. Have it looked at sooner than scheduled if you notice increased breathing effort, free-flow, bubbles, or water in the second stage.
How do I rinse and care for a regulator after diving?
Make sure the dust cap is dry and firmly seated over the first-stage inlet before the regulator goes anywhere near water, because water inside the first stage is the leading cause of internal corrosion. Rinse in fresh water without pressing the purge button, since purging while depressurized can draw water back into the second stage. Shake out the water and hang it to dry with the hoses in wide, gentle loops rather than tight bends.
Can I fly with a scuba regulator?
Regulators travel well and are usually best carried in hand luggage where they will not be crushed or lost. A regulator holds no gas of its own, so there is nothing inherently problematic about it on an aircraft, though the airline and security screeners always have the final say. Pack it dry with the dust cap in place, in a padded regulator bag or wrapped in soft gear.
Can I use my regulator with nitrox?
Many modern regulators are supplied as suitable for nitrox mixes up to 40 percent oxygen, which is the widely used recreational industry standard, while anything above that requires dedicated oxygen-clean equipment and procedures. Confirm what your specific regulator's manual states, and follow your nitrox training and your fill station's requirements. Never assume a regulator is oxygen-service clean simply because it looks clean or is new.
What is the difference between DIN and yoke regulators?
A yoke (A-clamp) fitting clamps over the tank valve and is the most common connection across much of the recreational world, while a DIN fitting screws into the valve and is standard in much of Europe and in technical diving. DIN captures the o-ring inside the threads, which many divers consider more secure, but yoke is often what rental cylinders provide. Adapters exist in both directions, so check what is used where you dive before deciding.
What is the octopus regulator for?
The octopus is your backup second stage, carried so you can share air with a buddy who is out of gas, or breathe from it yourself if your primary fails or free-flows. It is normally on a longer, brightly colored hose so it is easy to find and hand over under stress. Secure it in the triangle between your chin and the bottom of your rib cage so it is instantly accessible and not dragging through sand or coral.
How should I store a regulator between dive trips?
Store it fully dry, out of sunlight, with the dust cap in place and the hoses in wide loops rather than tightly coiled. Avoid hanging it by the second stages for long periods, which stresses the hose fittings; laying it flat in a padded bag or hanging it by the first stage is kinder. If it has sat unused for a long stretch, have it checked before your next trip rather than assuming it is ready to dive.
What connection does the Mares R2S first stage have?
This listing (MPN 416232INT) is the INT connection configuration. Mares also publishes a DIN/INT NX version of the same 2S first stage, so check which connection type matches your tank valve before ordering.
How many ports does the Mares R2S first stage have?
The R2S has four low-pressure ports, each 3/8 in UNF, for a primary second stage, octopus, inflator hose, and drysuit hose. It also has one high-pressure port, 7/16 in UNF, for a gauge or transmitter.
How much does the Mares R2S first stage weigh?
The R2S weighs 608 g (21.4 oz) in the INT connection configuration and 432 g (15.2 oz) in the DIN connection configuration.












