Malossi uses the best materials to produce it's viton drive and flyside crank seals, they consist of a steel core covered with fluorinated rubber (FKM/FPM - Viton) and the inner running surface, which has direct contact with the crank and creates the sealing surface is made from PTFE (Teflon) ensuring they run with low friction even at higher speeds. Both materials are made by the manufacturer DuPont.
  Both of these are very resistant to wear, so come highly recommended over standard nitrile seals and are essential with the addition of Ethanol to modern fuel/petrol
 
Benefits of using Viton Malossi seals:
Very low wear
High heat resistance
Extremely low friction resistance
Resistant to almost all chemicals
perfectly suited to higher revving / tuned engines