Push-button quick-detach sling swivel for 1-1/4" webbing, compatible with QD sling attachment points. Manganese-phosphate finished steel.
This is basic stuff on a modern self-loading rifle. Compared to traditional sling swivels this allows the webbing to un-rotate in case it twisted a bit when you threw the sling over your head. Also being able to quickly detach from your rifle might be important in some situations.
Made in USA.