GsP Airsoft features the Umarex Heckler & Koch M110A1 CSASS AEG in this airsoft gun check episode. The HK M110 A1 is a full-metal S-AEG airsoft rifle based on the US military service rifle. It has a 455 mm long, 6.03 mm diameter precision barrel and an adjustable Shoot-up for accurate shooting. It can mount tracer and silencer units on the muzzle with M14x1 thread. It has an ambidextrous fire selector, bolt catch lever and magazine button. It has a Picatinny rail and M-LOK slots for accessories, and a removable iron sight for close quarters combat. It has a 5-stage collapsable stock that fits Umarex B, C, D and E batteries with LiPo checkers.