UltraFlask™ 450 ML


Part of our ultra-light series, the 450 ml is so light, you might forget you brought it. Weighing in at just over an ounce, it’s optimal hydration, no matter what kind of runner you are. Its pliable material conforms to most pockets, it shrinks as you drink to minimize water movement and it can be used with or without the tube. Ultra light weight, ultra useful.


  • The UltraFlask 450 flask fits easily in most hydration vest, belt or pack pockets
  • Soft material conforms to any pocket for a comfortable carrying experience
  • Flexible design shrinks as you drink, reducing water movement on the run
  • High-flow bite valve auto-seals after each sip, eliminating annoying drips
  • Includes removable/adjustable drink tube; cut to a custom length or mount bite valve directly to cap
  • Large 42mm opening lets you fill the UltraFlask easily with ice and drink mixes
  • Made of ultra-durable, abrasion resistant TPU & RF welded seams for superior durability and elasticity
  • Can be frozen or filled with hot water (max temp 60° C / 140° F)
  • Top-rack dishwasher safe
  • Safe and reliable, 100% BPA & PVC free


450 ml / 15 fl oz

39 g / 1.3 oz

165 mm / 6.5 in x 60 mm / 2.36

Thermoplastic Polyurethane; Silicone; HDPE

Frequently Asked Questions

How do I clean my UltraFlask?

All of our SoftFlasks are top-shelf dishwasher safe so they are very simple to keep clean. If you are fueling with energy gels or mixing your own nutrition mix, we recommend using a bottle brush or Bottle Bright to clean out any residue. The bite valves and tubes can easily be removed for cleaning as well. Our Cleaning Kit provides you with both a tube brush and tablet of bottle bright to soak your valves in.

Write a Review

Customer Reviews

By Mauricio

I love this product for MTB rides

This is a great product, well designed and very useful for long rides on MTB, when you really want to go light as soon as possible.

The only issue I have is that either my unit is missing a part or it's me who just can't understando how to cut the tube and re fit the valve. ¿Is there any video about it?

By Bren

Perfect for snow skiing

I just got back from a ski trip and had so much trouble finding a way to carry water. I didn't want a back pack or something heavy. I found this bottle and totally wished I had it before my trip. It is light weight, collapsible to fit in a pocket or fanny pack.

By Abby

love this product!

Good size for using out on the trails or on long road runs or hikes

By Sara

Great for running

I love how lightweight and comfortable this soft bottle is when I use it in my running vest – I use it on long road runs and also out on the trails. I barely notice it in my pack, which was a change from using hard plastic water bottles in my vest. I like that when I’m finished with it, I can fold it up really small to store it before I fill it with water or electrolyte mix again.

You might also like...