Each BC13HPSS kit includes: 2 x 316L Stainless Steel Pistons (OD = 30.0 mm / Length = 35.0 mm) - 2 x Pressure Seal - 2 x Dust Seal - 2 x Rubber Boot A - 1 x Rubber Boot B - 1 x Bleed Nipple - 1 x Bleed Nipple Cap - 2 x Copper Banjo Washers - 1 x Pot of Red Rubber Grease ---- Red rubber grease is included to provide lubrication for assembly, protect from dry burn, and prevent swelling and hardening of rubber hydraulic component seals. Each polished 316L stainless steel 'Lifetime' piston is to replace damaged or corroded OEM caliper pistons. Type 316L is an austenitic chromium-nickel stainless steel containing molybdenum. This increases corrosion resistance, improves resistance to pitting from chloride ion solutions and provides increased strength at elevated temperatures. Type 316L is one of the highest specification stainless steels available - superior to both 303 & 304 grade stainless steel.