SILCA PRESTA CHUCKHow Much Silca Could A Presta Chuck Chuck?When you're short on time and need to inflate your tires quickly, nothing is better than a Silca Presta Chuck. This chuck is used by many pro teams and shop mechanics. It is made from aluminum, making it much harder than brass, and the full synthetic elastomer 242 gasket provides a perfect seal with its two-stage gasket sealing geometry. The pressure amplifying dome geometry uses air pressure to clamp the valve stem. Features Full synthetic elastomer 242 gasket is 5x the durability of traditional rubber materials Two-stage gasket sealing geometry is optimized for all Presta valves Pressure amplifying dome geometry uses air pressure to clamp valve stem | Silca | Presta Chuck Presta Valve, Aluminum | Rubber