Something more along the lines of this:
Would work a bit better because you can adjust the width between each handle. The piece of equipment you posted looks like you'd be using a very narrow grip as it comes in just one piece.
You could even use two cheap belts and loop them around your pull up bar to use as handles for a neutral grip. Two adjustable military style fabric belts would probably work best. They don't cost much and you can adjust them to any length by just unbuckling the clasp, looping it into the proper length around your pull up bar, and then cutting the remaining fabric off. They aren't very expensive and they'd definitely be sturdy enough to use. Just search on Amazon or something for "military style belt" and you can see what they look like. They'd be easy to quickly put on your pull up bar after you've adjusted them and also easy to remove.
They don't have any other bars at your gym? How about gymnastics rings? Rings can be adjusted to any height - you could get your own rings, bring them with you to the gym, and use them on the bars on the power racks. Or you could buy handles like these, which I own and work really well for me; those would lower the distance you have to reach too, though not by as much as rings would.
That said, I do think it's a great idea to get a pull-up bar for home - you can get in a lot more volume and progress faster that way!