An airbrake is cutting the air flow before the piston hits the bottom of the cylinder, creating an air damper that will reduce the impact noise, possibly at the cost of muzzle energy reduction.

Silverback Advanced Piston Head for Original SRS & TAC41 'AEG' Cylinder Head
Metal Construction
Design For Upgrade the Original Parts
Viton Oring with a ventilated design.
No airbrake, short, medium & long airbrake options (for 4.00 mm internal nozzle – for original SRS & TAC-41 cylinder head
POM piston ring
NBR 80° Oring damper
Stainless steel CNC construction, for additional piston mass (from 30.2 up to 31.7 grams, instead of 7.6 grams for the original piston head)
Suitable For Silverback SRS A1/ A2/ M2/ TAC41P Series Airsoft Sniper Rifle Airsoft Guns