This is a replacement shim for the Premium Titanium version of the Rogue's Ring just in case you lost the escape device or want a spare handy.
This product is not compatible with the Stainless Steel Rogue's Ring. The Titanium version of the ring has a special groove built-in to hold the shim in place. The Stainless Steel version does not have this feature and the shim simply wont' stay hidden under the ring.
If you are buying a new Rogue's Ring, you do not need to purchase this item as it already includes one escape device.