This piston head feature:
– Viton Oring with a ventilated design.
– No airbrake, short, medium & long airbrake options (for 4.60 mm internal nozzle – for TAC-41 GBB cylinder head only).
– POM piston ring
– NBR 80° Oring damper
– Stainless steel CNC construction, for additional piston mass (from 30.2 up to 32.2 grams, instead of 7.6 grams for the original piston head)
 
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.
 
Compatible with:
 
– original SRS piston (SBA-BPS-13)
– original TAC-41 piston (SBA-BPS-30)
– variable mass piston for SRS (SBA-BPS-18)
– variable mass piston for TAC-41 (SBA-BPS-31)
– steel variable mass piston body (SBA-BPS-XX)
 
Video link Here
 
Please Note
When buying parts from Longbow BB Ltd, you confirm you have the required ability to install and tech your airsoft replica as required. 
Longbow BB Ltd do offer a paid for service option for us to look at your rifle and try to solve any issues you maybe having. 
We need to manage your expectations as we (Longbow BB Ltd) are unable to provide extensive hours of tech advice for parts purchased that have been installed by yourself. 
All parts are inspected before dispatch to ensure product quality.