The ORIGINAL Weight Adjustable piston is back, with an improved design and material tweaks. The Tac-41 W.A.S.P package features: 1 x Tac-41 W.A.S.P Base Piston body 1 x Rear Sear 1 x Rear Guide Ring 1 x Front Guide Ring 1 x Plastic Sleeve (Light) 1 x Steel Sleeve (Medium) 1 x Steel Sleeve (Heavy) 1 x Non-Airbrake Fitting 1 x Full Airbrake 1 x Mid Brake 1 x Injection Moulded Cup 1 x One Piece Stainless Steel Spring Guide 1 x Spring Guide Oring Notes: – When using the airbrake, please bear in mind this is only effective up to a certain point in terms of power gains over the non airbraked setup. This is due to how the air works inside the cylinder, at a certain point the sheer power of the spring and piston result override the airbrakes function and slow to air down to much causing a loss. This “break point” will depend entirely on your setup. That being said, due to the guide ring and cup design alone, even at 4.5J, weighted and unbraked the sound is still reasonable. - Piston works with most 13mm springs. However some of the lower power SBA springs aren't the same spec and may bind - Ensure cup is correctly lubricated before use, silicone oil is best. - Due to the rear guide design of the Tac-41 W.A.S.P you may need to lower your sear height to allow the sear to slide over and release. If you find the piston does not release or sticks, lower the sear height. - Please ensure piston is precompressed before tightening cylinder head, as cylinder threads can damage the cup if they get pinched (only with Stock SBA cylinder head, not an issue with SniperMechanics cylinder head). Push piston down and use a small tool to latch the sear so cylinder head can be installed, or use a hex key through nozzle to push piston enough to clear threads.