They look just like the Pittsburgh Tools strap wrenches that I got on e-Bay a while ago that were pure rubbish. They won't keep their grip on anything for long, and don't have enough grip, or traction.
I have some
Kobalt strap wrenches from Lowe's that are excellent. They come in a two pack (large and small) are very grippy, and have a lifetime warranty. The only downside is that they have a metal link that can scratch a light if you aren't careful. I will likely pick up a two of these
Whirlpool strap wrenches the next time that I make it out to a Lowe's. The design looks like it will work well for flashlights. Just remember that the tooth area goes toward the direction that you are turning.