The use of unsterile clay to assist in the drying out of umbilical cords has been associated with neonatal tetanus . It is a hemostat with a little wire attached the allows the placement of a simple rubber band on the cord stump. Similar to a rubber band used in dental braces. It is so small that it allows no return blood flow into the stump and there is not the hassle of a large metal or plastic clamp.
Parents are so scared of a little blood from the stump.
I need to know that the bands don't allow much spotting. Many of us clamp first with a hazeltine or kelly and then use the averbach later after everything has settled down and parents are ready to dress the baby. So often an hour or more has passed before we use the cord-bander. The only trouble I had with the cordbander was once when it when down too far to almost the skin edge. Since then I keep a kelly nearby to stop it from going too far.