This unique bright red gasket borrows from industries which require air-tight seals in the harshest of environments. It tests to a life expectancy of more than 5X the carbon filled rubber or Buna-N materials used previously. New Two-Stage seal geometry seals on both valve stem and at the base of valve core threads resulting in a more positive seal and improved durability. The new gasket slips onto the valve stem with a satisfying 'click', while unique internal geometry actually utilizes line air pressure to compress the gasket onto the valve stem: the higher the pressure, the tighter the seal. This design is so iconic we've found more than 20 companies world-wide making pump heads and gaskets copied from this, but none of them can come close to the precision and technology of the SILCA 242.
Delivered quickly as promised. Item is one of a kind and works great. Just make sure to orient it in the chuck as pictured on the listing page.
I order these three at a time. When they are new, they work like a champ, but as the rubber wears down, they lead and do not hold the stem tightly and securely. I attribute that to the ribbed stems on the Conti tubes I use. I've used smooth stems in the past once in a while, and I bet the rubber would last longer if I used them exclusively. Average life expectancy is about 12-18 months, pumping up 2x tires 3-6 times per week. When they are new, they are great!
Excellent replacement. Good fit in Chuck and performance is fabulous.