Newly designed gasket for all SILCA disc adaptors Features: Fully Synthetic Elastomer Base Material 5X the durability of traditional rubber materials New Two-Stage sealing geometry optimized for all Presta valve stems Fits all prior SILCA disc wheel adapters (though at reduced max hands-free pressure) NOTE: Compatible with all prior SILCA disc adapter designs, however, the limited height in the adapter head will prevent the valve stem from fully engaging the gasket. Generally the 252 gasket in a CP1 will hold a minimum 120psi on any size or type of valve stem, while it will hold 70-80psi when used in older SILCA adapters. The Story: The classic SILCA 25.1 gasket has been replaced after more than 20 years in the market. The new 252 gasket utilizes a high tech and very red, fully synthetic elastomer base material rather than a carbon black filled natural rubber of previous designs. This unique bright red gasket borrows from industries which require air-tight seals in the harshest of environments, and tests to a life expectancy of more than 5X the carbon filled rubber or Buna-N materials used previously. In tests with a major disc wheel manufacturer, the new SILCA CP1 Disc Wheel Adapter with 252 gasket literally blew away the field by posting a blow-off pressure of 393 psi where other designs were unable to reach 120psi. NOTE: Compatible with all prior SILCA disc adapter designs, however, the limited height in the adapter head will prevent the valve stem from fully engaging the gasket. Generally the 252 gasket in a CP1 will hold a minimum 120psi on any size or type of valve stem, while it will hold 70-80psi when used in older SILCA adapters.