Why does the anastomosis have a rubber ring

The role of suture wound. After circumcision, the titanium nail of the anastomosis plays a role in suturing the wound, there will be a ring of rubber ring in the middle of the titanium nail, and it does not need to cut itself, one week after the operation, the titanium nail will start to fall off, with the gradual fall of the titanium nail, the rubber ring will also slowly fall off by itself, and it does not need to be cut.