Enginetech's high quality valve stem seals are available in three categories, Premium Positive, Premium Umbrella and OE.
Enginetech Premium Positive seals are metal clad with high-temp Viton® elastomer sealing lips. All Premium Positive seals are designed to work with valve stems from 0.005" under to 0.015" over. Most of these seals can be used as a universal fit on normal guide sizes such as 0.482", 0.500", 0.512", 0.530", 0.562, 0.625" etc. Stem diameters range from 8.00mm to 3/8".
Enginetech Premium Umbrella seals are high-temp Silicone with garter springs to retain stem interference. All Premium Umbrella seals are designed to work with valve stems from 0.005" under to 0.015" over. Most of these seals can be used as a universal fit on normal stem sizes such as 8.00mm, 5/16, 11/32" and 3/8".