Airsoft Master gives us an overview Knights Armament SR-16E3 CQB AEG which is one of the 2015 releases from Echo1 USA Airsoft... "The Knights Armament SR-16E3 CQB MOD2 Tan features an 11.5 inch metal outer barrel with an orange tip flash hider compatible with the Echo1 MK1 SR556 Quick Detach mock suppressors. The fore-end is a 10” URX Keymod Rail System licensed by KAC (Knights Armament Co) which comes with a one 9-slot and two 5-slot keymod rail segments.