If using a TAC-41 Polymer or Lite Sport version, you will need the metal spring guide and base. This SAP piston kit comes with an edgi spring guide which replaces the Silverback spring guide - you will need to reuse the Silverback spring guide base. 
 
A brand new Shock Absorbing piston from EdGi custom works.
 
SAP - Shock Absorbing Piston 100G Base weight - 150G maximum
316L Stainless Steel
Weights included: 120G, 140G, 150G
Sylicone Damper
Threaded Airbrake for the ultimate in fine tuning
Dual Delrin protection guide ring
Aluminum Barrel Spacer for base weight
Spring Guide in Stainless Steel with Bearing and Rubber base Pad for wobble free operation
13mm Spring guide shaft
 
 
*Do not use lubricant with any Silicone ingredients - this can cause the shock absorbing pad to swell. Approved Lubricant can be found here
 
Please note this product may have up to 25 working day lead time.
 
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.