Also known as square ring, rectangle ring, rectangular ring, bag buckle, strap loop, strap holder, looploc buckle, etc. Used for adjusting webbing or connecting. Size ranges from 4 inches to half inch, which can be flexibly applied on different uses. Application: backpack, pet collar, harness, clothing, shoes, baby stroller, baby chair, life jacket, belt, camping gear, outdoor & mountaineering equipment. military equipment, medical arm sling, etc. We have also tri-ring, O-ring, D-ring, strap keeper for choices.