I have one of these cheapy ones and it is QD - you push down the lever on the front and it'll slide on and off a rail http://www.ebay.co.uk/itm/Mount-CREE-LED-Flashlight-light-fit-for-Pistol-Glock-Handgun-Weaver-Picatinny-/281086552465?pt=UK_SportingGoods_Hunting_ShootingSports_ET&hash=item4172106991