Each BC253M kit includes: 1 x Piston (OD - 12.7 mm / Length - 37.0 mm) - 1 x Return Spring - 1 x Pressure Seal - 1 x Guide Seal - 1 x Gaitor Boot - 1 x Circlip - 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.