I think I have the sling you are talking about. I received it as a present it came from Slogan Outdoors. They advertised on the outdoor channel, but I have not seen their advertisement in a while.

The sling is an Ultraflex sling made from thermoplastic that won't slip off your shoulder. It really works too!! The only problem is that it is a little bouncy when you walk with the gun on your shoulder. It has two straps so you can use it backpack style. Good for crawling and dragging out deer. I looked on the web for their website, but could not find it. Do a search for the Ultraflex and see what you can find. Good Luck!