bolt ring closure(Bolt Ring Closure – A bolt ring is a closure ring that holds the cover on to the body of the container by encompassing the cover and the top of the container in a groove. This ring is then tightened by a bolt that pulls the ends of the rings together. A calibrated torque wrench is used to confirm proper closure (to meet UN Rating requirements) thecarycompany.com, gosthelp.ruFiriel)
