DS-1 Flow-Through Valve Cap is Designed for High Pressure Truck Tire Service • Seals Like a High Pressure Valve Cap, Yet Offers the Convenience of an Inflate Through Extension • Performs Like a Check Valve — Seal Becomes Tighter in the Event of a Core Failure • Reduces Pressure Check Time by 65% Offering an Efficient Money and Labor Savings Alternative to the Common Valve Cap • Heat Resistant Grommets Provide Additional Protection for the Extended High Temperature Running • Consists of a Tough, All Metal Housing, Precision Fit Brass Components and Durable Self-Sealing O-Ring