Jeidanten's video demonstrates the installation of the SRU SARB 15 AR-15 M4 GBB bullpup kit. This airsoft kit, designed for Mil-Spec GBB AR-15 lower receivers, features a 15.3-inch length of pull and a total length ranging from 26 to 29 inches with a 16-inch barrel. The kit itself measures 20 inches without a handguard and 25 inches with one. Weighing in at 940g without and 1280g with a handguard, it boasts a polymer shell, 304 stainless steel trigger linkage, and 6061 T6 aluminum alloy short buffer/sling buckle. Other components include polymer trigger/safety/magazine catch, rails, and front adapter, as well as TPU gun stock pads. An optional stamped steel front handguard is also available. Compatibility extends to various short buffer systems, including Maple Leaf-Hummingbird, GBL, C&C Tac, and SRU's own MARUI MWS special short-bolt action.