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