Omega Pacific Rappel Ring
I do use this device and others like it, although it is not a belay or rappeling device.
This item is most accurately part of an anchor system. When rappeling from a climb and the conditions permit this device should be used to build the anchor you are going to rappel from.
When using this as part of an anchor I recommend using two. If possible use one inch webbing and two of these rings. Thread the two rings and sling a horn or tree or other natural anchor. I prefer multiple anchor slings to my ring anchor. Once you have completed the anchor and you are positive that it will support the required weight, thread your rope through the rings only and in each end of the rope tie double fisherman's knot, slide your rope on through to the middle ( you did mark the middle of your rope) now your ready to set up your chosen rappeling device and rappel as usual.
The big difference is you did not have to leave behind multiple expensive pieces of protection as an anchor.
Remember when your life and the life of others is on the line, make sure your anchor is bombproof. Sometimes you will have to leave more expensive hardware behind.