Unique moulded holster for quick, one-handed Flask access. 5ox Nutrition Flask with Race Cap. Race Cap with high-flow, one-way valve opens and closes automatically and offers a quick shot of gel - no need for intense squeezing or sucking. Universal attachment plate: use in place of bike cage or attach anywhere on bike with Velcro straps or zip ties. Silicone base ensure the propellor won't slide on frame or damage bike