Swann morton 4307 smor ii retractable scalpel handle and replacement blades swann morton 4307 the swann morton smorii retractable scalpel handle features a forward position to assist with easy blade fitment and removal along with audible clicks to indicate the mid usage position and the rear safe position for when the knife is not in usethe knife is supplied complete with two sm01 blades and can also be used with swann morton sm01b sm02 sm03 sm03b and sm04 blades swann morton 4307 smor