Re: SF 6P & G2 Hosters?
Don't know if they have changed the sheaths since I got mine but I don't recall my V21 having any metal in it. The V25 clip-on does, and that is also a well made sheath for the 6P/G2 line.
The Surefire V21 has been on my Fat Boy for a long time -- easy to undo the Velcro retaining strap (the part that goes around the belt or as I have used mine over the PALS webbing on a pack or bag) and completely remove the sheath. Easy to open the sheath and remove the light. The strap over the light is long enough that if you use a filter or beam shaper on the light, it will still be covered and won't let the light come loose.
Surefire sheaths are available in nylon or leather.
This is an excellent example of the quality you sometimes get when you pay a bit more and mine was well worth it. Very sturdy and the work well. The only downside if any is that the Velcro is noisy, but then again the high quality Velcro often is.