FIELD: materials handling; stopping of vessels with threaded neck and engagement rim in lower portion of neck. SUBSTANCE: safety ring is provided with outer peripheral thickened portion with preset value of deformation. This portion provides compression and bending of lower part of ring, when turning on the device, in direction towards vessel neck axis, until lower inclined surface of inner lock projection is set in position close to parallel relative to stopper axis. EFFECT: improved quality of stopping. 10 cl, 6 dwg
