The crank handle thingie to tighten the window spring is well-built and effective. I have absolutely no problems or issues with the piece itself--if you need one, buy it!I would ask, though, that the seller provide a brief instruction sheet (if one is even available) on how to temporarily remove the window, access the bottom end of the spiral counterbalance spring from within its plastic housing, how many turns, etc. I mean, I did it OK, through trial and error, but I always like knowing there's an instruction set somewhere just in case.Here's a hint--if the spiral "twists" have totally fallen out of the aluminum tubes (and the plastic nose-pieces), they CAN be reinserted! Just grab the spirals as close as possible to the end you're inserting (the end with the little plastic "button" on it), and push straight and hard. But if you push TOO hard, and bend the spiral--you didn't hear it from me!