A buckle including a first buckle portion having an engagement member and a second buckle portion having socket arms forming a socket for releasably engaging the engagement member. A sleeve member is reciprocatably disposed about the socket arms between first, second and third positions, whereby the sleeve member in the first position prevents expansion of the socket arms so as to retain the engagement member, and the socket arms are expandable when the sleeve member is in the second and third positions so as to permit release of the engagement member from the socket and insertion of the engagement member into the socket.