Specifications:
length when fully extended: 122 mm / 4.8"
length when fully collapsed: 102 mm / 4"
stroke length: 20 mm / 0.787"
weight:  grams 160 / 5.6 oz
weak buffer spring included
 
Best for blowback systems, far more effective Hydraulic Buffer System
 
Our drop-in Hydraulic Buffer System absorbs felt recoil far better than any regular buffer and reduced bolt carrier speed, keeping your rifle more steady and allowing for quicker follow-up shots (faster sight recovery time). It also eliminates bolt bouncing, resulting more reliable system.
 
Made of strong stainless steel combined with Long Life springs and durable rubber to maximize life cycle. The system comes with weak buffer spring to compensate for additional spring inside the hydraulic buffer.