Abstract: A multi-purpose device with concealed locking means having a first tube, sliding tube, lock hole, locking button hole, locking button, sheath, bias element, tip, handle, compression ring, and friction gasket.

Abstract: A single use tamper resistant syringe having a locking member which prevents retraction of the plunger after the latter has been fully depressed and discharging the contents of the syringe. The proximal end of the plunger is provided with an abutment and the inside of the barrel is provided with dogs which are biased inwardly. When the plunger is depressed and the abutment slides by the dogs the latter extend into the barrel to block retraction of the plunger. Tampering of the locking arrangement prior to use of the syringe is prevented by providing a detachable piston cap at the distal end of the plunger so that when the plunger is removed prior to use the cap is dislodged by said dogs and remains within the barrel of the syringe thereby rendering inoperative the syringe.