If you, like me don't change strap all the time, and just want the strap to stay on, and be secure, this is a well worth product.
A big bonus is you don't have to change knobs on your instrument, but it's not a fast strap-changer, like some of the secure lock systems.
I'm using these without any problems on both a lightweight violin bass, as well as a heavy as .... Stingray bass.
If you just want the strap to stay on, and don't want to modify your instrument with snap-on systems, this is a good alternative.