UltrAspire introduces yet another milestone in hydration history! All the benefits of the sport bottle without the downsides and all the benefits of a soft flask without the usual problems such as taste and staining from carbohydrate drinks. This great feeling, easy stowing bottle is a hybrid between a hard bottle and a soft flask! The lightweight super-squeezable UltraFlask™ stands alone, is fillable and easy to clean, has a high flow and fast recharge, is soft, flat, and stable against the body, is easily accessed, and returned to a vest pocket even when empty, and it's great for waist packs too! The UltraFlask 550 Hybrid Bottle is BPA free.