A handcuff comprising a bolt and a bolt spring which work to double lock the handcuff. The bolt comprises an underside having teeth which are engagable with the teeth of a jaw. The underside of the bolt comprises a groove through which a stud disposed on a cheek head of the handcuff is positioned to thereby further secure the bolt in position when the handcuff is locked. The bolt further comprises an upper side comprising a groove, a spring stop, and a detent. The bolt spring comprises a body bent to form a side wall which bridges a first spring leg portion to a second spring leg portion, wherein the first and second spring leg portions engage with the upper side of the bolt to hold the bolt spring in a first position. The spring stop prevents the bolt spring from over-rotation, and therefore, prevents breakage of the bolt spring.