T-N.T. Studio APS-X HOP-UP System H+ Retrofit Kit for GHK M4 GBB (320mm) Net-Weight-(g)_570 It can also be used

It can also be used as a scope riser mount

The inner barrel is a precision one with 6

Madbull has released their next generation Metal Bodies and is a perfect addition to their impressive line of high quality upgrade parts

As it happens

Operated by winding the compression spring

T-N.T. Studio APS-X HOP-UP System H+ Retrofit Kit for GHK M4 GBB (320mm) Net-Weight-(g)_570 It can also be usedT N. T. Studio APS X HOP UP System H+ Retrofit Kit for GHK M4 GBB (320mm) Aluminum Construction Design For Upgrade the Origianl Parts The kit ensures better accuracy due to better and finer tuning of the hop up. Suitable For GHK M4 Series Airsoft Gas Blow Back GBB Rifle