the OMM MtnFire 15 + 2 X 350ml Flexi Flask

the OMM MtnFire 15 + 2 × 350ml Flexi Flask

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The OMM MtnFire 15 + 2 × 350ml Flexi Flask is OMM’s largest and most spacious Fire race vest , designed for long, remote running adventures, ultra-marathons and Mountain Marathons where safety, stability and pack volume are critical. With a 15-litre roll-top compartment at the back, you can carry a full two-day MM kit , extra dry layers, food and first aid – and still run efficiently. The vest comes complete with two 350ml Flexi Flasks .

The carrying system is built around a stretch mesh harness and body-hugging pockets that keep your pack close to your body and reduce bounce even when the vest is fully packed. The rear compression system and roll-top closure secure the contents and allow the volume to be reduced when the load is lighter, providing the same stable feel on shorter trips.

For on-the-go access, the MtnFire 15 features seven large stretch front pockets , two of which are zippered , with plenty of room for energy, a map, compass, hat and gloves. The rear 15-liter roll-top bag is perfect for gear that doesn't need to be accessed often, but needs to be carried safely and securely.

Hydration solutions are flexible: the vest comes with 2 × 350 ml Flexi Flasks , the front pockets also hold up to 500 ml soft flasks , and the rear hydration pocket takes up to a 3 L Ultra Bladder . This makes the MtnFire 15 adaptable for everything from long training sessions to multi-day races.

Despite the large capacity, the weight is low for the class – approximately 245 g (leanweight) – making the MtnFire 15 an obvious choice when you need maximum volume without compromising on running feel and stability .

Features & Benefits

15L roll-top race vest – holds two-day Mountain Marathon kit

Very stable carrying – stretch mesh keeps the load close to the body

Ultra-light for its size (approx. 245 g) – effective even when fully packed

Supplied with 2 × 350 ml Flexi Flasks – ready to go

Quick access front – 7 large pockets for essentials

Compressible volume – also works on shorter trips

Features

15 L water-resistant roll-top compartment at the back

Rear compression system for reduced bounce

7 large stretch pockets at the front, 2 of which have zippers

2 × 350 ml Flexi Flasks included

Front pockets for up to 500 ml soft flasks

Hydration pocket for up to 3L Ultra Bladder

Breathable 3D mesh in the harness

Reflective details

Ability to carry poles

Technical specifications

Volume : 15 L

Weight (lean weight) : approx. 245 g

Hydration : 2 × 350 ml Flexi Flasks (included)

Hydration bladder : compatible up to 3 L Ultra Bladder

Material : 3D mesh harness, Nylon 210T, stretch mesh

Sizes : S, M, L

Suitable for

Ultra races, mountain running, mountain marathons and multi-day adventures – when you need maximum packing volume in a runnable, stable race vest .

Care instructions

Rinse the bottles after each use. Wash the vest on a gentle cycle according to the manufacturer's instructions and let it air dry.

The OMM MtnFire 15 is a body-hugging unisex running vest with 15 liters of pack volume and two included 350 ml Flexi Flasks. Choose your size according to your chest circumference and try the vest on with a realistic pack to ensure a stable fit.

Size chart

The size ranges overlap slightly, so you can choose between a tighter performance fit and more room for clothing and adjustment.

How is the OMM MtnFire 15 sized?

The MtnFire 15 has a body-hugging unisex fit designed to keep the pack stable while running. Use your actual chest circumference instead of your usual women's or men's clothing size.

The vest should fit close to the upper body without restricting breathing. Since the model holds 15 liters, it is especially important to check the fit with a pack in the back compartment.

Our size recommendation

• Choose the smaller size if you are in an overlapping range and want a tight fit over thin running clothing.
• Choose the larger size if you want more adjustment space or use the vest over a shell jacket and warmer layers.
• At a chest circumference of 94–95 cm, S gives a tighter fit, while M gives more room.
• At 105–106 cm, M provides a tighter fit, while L provides greater adjustment.
• If you plan to carry a lot of gear, you shouldn't choose a larger size just for the sake of packing. The vest size should still match your chest circumference.

How do you measure?

Measure around the widest part of your chest, just below your armpits. Keep the tape measure horizontal and close to your body without pulling it tight.

Please measure over the clothes you would normally wear under the vest. If you are using it in cold conditions, you should measure over the corresponding midlayer or shell jacket.

Try the vest with packing

Fill both of the included 350ml bottles and pack the back compartment with approximately the amount of gear you plan to carry. Distribute heavier items close to your back and use the vest's compression system to keep the contents in place.

Adjust the vest gradually and check the fit by walking, jumping and running a short distance.

Check the fit

The right size means that:

• the vest does not bounce or move when running
• you can take deep breaths without pressure on your chest
• the bottles sit securely at the front
• the pack does not pull the vest backwards
• the shoulder area lies evenly without point pressure
• the vest does not rub at the neck or armpits
• The straps have adjustment in both directions.
• you can move your arms and upper body freely

Check the fit both with a light pack and with the heaviest load you normally expect to carry.