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.
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.
my Silca floor pump is 30 years old. I recently replaced this gasket after years of extensive use. Great to know they can be counted on to keep making parts to keep the best pumps going