Ever wondered which pistons you should purchase to provide the greatest host compatibility for your Osprey or Octane? SilencerCo has removed the guesswork with the introduction of the limited-edition Piston Kit. - The Piston Kit features five pistons with a black nitride finish for increased wear-resistance and lubricity. What's more you're receiving five pistons for the price of four - with three o-ring packs also included free of charge. - INCLUDED: - .578 x 28 Piston - 1/2 x 28 Piston - 16mm x 1 LH Piston - 13.5mm x 1 LH Piston - 9/16 x 24 Piston - Booster Assembly O-Ring Pack - M13 O-Ring Pack - M16 O-Ring Pack