Cometic EST Complete Overhaul Kit For Harley EVO EST (Extreme Sealing Technology) kits are made for any builder who demands the best and appreciates the long-term value for his/her dollar. Features: Kit contains MLS head gaskets, steel Viton coated base gaskets, blue Viton valve stem seals and AFM material Race style exhaust gasket that won't fray into the port One-piece Evolution rocker box base gasket, which is made from a single layer of .020 thick embossed Viton coated steel Complete motor kit Replaces OEM 17355-92