You can control the tension and, in the learning video (downloadable) you are given simple directions on how to repair the reel should the thread break.
The thread is about aas near to invisible as I've seen ... or not seen.

There are no instructions included about how to use this reel for magic, they only inform you how to adjust the tension, conceal it, and repair it; they said they’re not going to go into how to use it; I expected tutorial, but will learn myself.

The item I received was basically damaged. The caps were cracked and a piece was broken off. The reel itself doesn’t really allow the IT to retract into it. I am sure there is a way to adjust the tension and everything but tbh I tossed this right in the bin as soon as I opened it. Not worth more than $10 IMO There are much better reels on the market.

Maybe mine is just a little messed up but it won’t levitate most small lightweight items from the table to the hand, and adjusting the tension tighter in mine was a lil annoying; I think it can hold stuff up in different ways and accomplish other kinds of levitations and telekinesis and such but not really for levitating stuff up into the hand, maybe balled up paper and such; but yeah I am so glad I got a hold of “cup zero by twister magic” it is a breakthrough levitation system for me for sure and I surely recommend it if you are wanting to levitate items with more weights and have crazy great looking visual levitations that look like real magic;
But yeah for sure potential and usage for the right stuff with these reels.