These might appear a little flimsy and risky to those used to the full metal type, but I've been using these for about three years now and have never had a single failure. My decision to try these came about when the button hole in the bridge end of my strap started to wear a little and began to feel loose on my bass. I've had accidents in the past and wanted to prevent anything like that happening again. Prefering to gig vintage basses I didn't want to go remioving existing screws and buttons for the sake of not wanting to compromise the existing screw hole. These locks fit over your existing strap button without any mod to your expensive investment grade instrument and like I say: they haven't failed me yet and don't look like they're going to fail me either. At £3.00 a shot you can buy ahalf a dozen and still have change from your twenty. Can't recommend these enough.