The Silverback SRS upgrade or replacement piston cup is a first party original part designed to work with the SRS rifles' piston. 

Compatibility: 

• Silverback Desert Tech SRS A1 
• Silverback Desert Tech SRS A2 

Includes: 

• x1 Silverback SRS A1 / A2 Piston Cup NBR 70 degree (Black) for BPS-11/12/13/14