25XR AST 1st Stage

Product No: 416400


The 25XR first stage is extremely reliable and perfectly sealed thanks to the standard CWD kit. Perfect for any type of configuration with pre-oriented HP outputs.

Product Information


The 25XR AST first stage was created to mainly meet the needs of divers using the double tank or to be mounted on a stage. The first stage immediately strikes any technical diver's eye, due to the presence of preoriented Lp and HP outputs positioned on one side only. In fact, this model was created to have an assigned position. The hose exits are positioned so that they fall behind the diver during assembly. This feature makes it ideal for cave diving or in environments with limited passages.

The key features of the 25XR AST first stage are:

• All metal body
• Nickel and chrome plated marine brass
• Solid and compact one piece body
• Balanced diaphragm - DFC
• New ACT valve - Advanced Coating Technology
• Dry CWD kit for cold water
• DIN only
• Use with trimix, eliox, elitrox up to 150m
• 2 low pressure outlets (3/8 "UNF) all angled downwards
• 1 high pressure outlet (IPD: Intelligent Port Design - design with smart outlets) enhanced (7/16" unf)
• Extreme reliability - maximum safety
• Optimized breathing comfort
• Extreme depth, demanding dives and mixtures (helium, o2, nitrogen)
• Perfect hose positioning - no unnecessary output - ideal hose layout to avoid entanglement
• To be used with double tank but equally suitable for the configuration single tank or stage
• IPD: Intelligent Port Design
• Double configuration: satisfies all educational agencies from RSTC to different all technical uses, including cave diving
• Minimizes the risk of getting in the way, no kinking of the hoses and easy access to the taps knobs
• 2 watertight systems: isolate the main spring and valve from possible ice formation and/or contamination
• Resistant to cold water
• AST - Auto Sealing Technology. Keeps the first stage dry. Reliability without any compromises. The system is automatically activated by air. Tested with oxygen and low temperatures in demanding environments. Patented system


High pressure ports:
1 (7/16” UNF)
Low pressure ports:
2 (3/8” UNF)

Delivery & Returns


Fedex calculated rates for any order under $100 or for any expedited order.
Free shipping on any order over $100.



Any order placed by 12:00 PM EST Monday - Friday (excluding public holidays) will ship within 3 - 5 days. If you’ve placed an order after 12:00 PM EST or on a weekend, your order will process on the next business day. 

Orders placed with expedited shipping will ship out the same day if the orders are placed by 12:00 PM EST Monday – Friday (excluding public holidays)



All products may be returned for a full refund to the original payment method, provided

the items are returned to us within 30 days of you receiving the products and are in new 1st quality conditions. 

To initiate a return please reach out to us Monday - Friday 9:00 am - 5:00 pm EST at 1-800-874-3236, or email us at customerservice@us.mares.com .



Please ensure that any product you wish to return is unused, in its original packaging and has all tags still attached. You agree that it is at the sole and absolute discretion of Mares to determine if the product has been used. Shipping charges on all returns are your responsibility and are not subject to a refund.


  • Returned products must show no signs of use or wear and must be returned in its original packaging (e.g., plastic, clam shell,

mesh bag). All tags are still attached, no scrapes on the products, etc.



Unfortunately, we are not able to exchange products. We are able to refund your initial order, but you will have to place a new order online.