Thats it. there are several different Folding blades, most have muzzle rings the Berreta SMG ?(sub machine gun) has the T shaped lug to lock under the front of the gun. THese are very colelctable and not common, the brass one is very rare, that is the first i have ever seen for sale, and woudl have loved it for my collection. THere are a couple of use doign research ont eh folders at the moment and have 11 variations identified without the SMG version, and i have 4 of them on my site including the Berreta