The HydraPak Ultraflask Speed Bottle is designed for runners and outdoor enthusiasts who need hydration on the go. With its wide, stable UltraFlask design and durable 3D-welded bottom, it fits securely in vest and pack pockets. The soft TPU construction allows it to pack down flat when not in use, saving valuable gear space. The SpeedFill cap offers quick one-handed refills at aid stations, while the self-sealing, high-flow bite valve ensures zero drips. The wide 42mm opening allows for easy addition of ice or drink mix, and its compressible shape minimizes water sloshing. Compatible with 42mm threaded backcountry water filters, it's 100% BPA and PVC-free.