OG,
I have three similar wrenches:
1) Snap-on 5/8" x 9/16" double socket wrench,
2) Blackhawk 1316 1/2" single socket wrench with knurled offset handle, and
3) Walden 615 21/32" single socket wrench with knurled offset handle.
In 15-20 years of hunting, these are the only wrenches of this type I have seen.