The affordable S&T MK16 URG-I Challenger Line G3 AEG is reviewed in this video by Golgy, a Sunday gamer. The S&T MK16 URG-I AEG is a nylon fibre and metal airsoft gun with a G3 electronic trigger from S&T. It has a RAS handguard for attaching accessories, a 14mm CCW threaded muzzle, and a high capacity AEG magazine that holds 340 BBs.