Hydrapak Blaster Bite Valve
Here's what other sites are saying:
The Blaster Valve from Hydrapak represents an entirely new design. The intent was simple - produce the best, highest-flow valve on the market and they surpassed their goals. The high-grade compression-molded silicone sheath feels great in your mouth and features the highest water flow on the market. The Blaster Valve allows you to gulp water to cool your thirst.