They work awesome. I went with the heavy duty, and ended up only using 2 of them for standard tuning with 9g strings. They’re very spongy with smooth action, and as described, they are noiseless. Be aware though, you will still get resonant noise from behind the nut, so if you really want to stop all excess noise, they are best used in conjunction with a fret wrap or jimmy clip between the nut and tuning machines.