Seems like good quality, but it doesn't fit my trombone. My old spring had just three loops on each side of the key (3 mm per side), while this one has seven (6mm per side), making it much too wide to fit into the bracket on my trombone (1 cm wide in total, which needs to fit the key (mine is 3mm) and both springs), so measure your old spring and bracket before ordering. The web site doesn't provide the measurements, but it seems like you can estimate 1mm per loop on the springs. I tried to stretch it out to remove some loops, but that didn't work.