This handcuff is the popular patrolman model, and works with a barrel type key. The double lock system is thumb activated. Like most everything Clejuso makes, they are larger than their American counterparts. Clejuso make the world's finest cuffs. German workmanship makes these standard style handcuffs some of the very best on the market. Easy press-in double lock button and swift swing-through ratchet motion. Made of high-grade stainless steel.