Adam

Here is the tie on type on my Jeffery 404. It is quite secure but needs to be looked at occasionally as they can wear a bit. the thong is easily replaced.

The advantages over metal are quietness as they cannot bang or click the barrel. They also will not mar the blacking as metal can.

If it gets wet it can shrink tight and be a bit harder to remove.

I also have the hooks on a 2 inch sling for my Doubles. it is easy on and off but can be noisy.