Oxygen Wrench

I was asked to print an oxygen wrench and could only find one on the internet (http://www.thingiverse.com/thing:897996/), but I didn't like the design. I think it's a marvelous looking object, but I have my doubts about how well it will hold up over time. So I whipped up some test objects for dimensioning, then added a quick handle. v2 will be more refined.

Update 8-2-15: I had too much time to play yesterday, and went through three more iterations. I tried a number of different designs, but found (as always) that simple is better. v4 is a slimmed down version of v1 with a horizontal and vertical slot. I had to increase X and Y by 2.5 percent to get a loose fit. At 100% size it was a snug fit on most of the bottles I tried, but I only have 7 on hand at the moment.

*I suggest printing O2 Wrench Test 2 first and checking for fit. Then determine how much to scale and apply that to the full size wrench.*