The 3-liter FastBack 4.0 Hydration Pack fits in place on your recumbent trike or bike with two adjustable bottom straps, for maximum attachment versatility. One strap wraps around the seat and the other anchors to your frame. Attach in whatever position best suits your situation. Works especially well with Catrike recumbent trikes. Works well with the FastBack Tool Pouch, FastBack Pump Pack, and CamelBak Hydration Bladders.