Strap Locks - Schaller and Dunlop

While there are several newer systems on the market, including those by Fender and Ernie Ball, for over 30 years, the main players in the strap lock market have been Schaller and Dunlop.  Here are the pros and cons of each system.

Schaller

Pros: Solid feel. Easy installation. Easy to use. No mistaking when they're locked.

Cons: No matter how tight you set the hexagonal nut (shown above the washer) that attches the lock to the strap, they eventually work their way loose. And I mean ALWAYS. You have to keep an eye on them, and occasionally tighten them.  Schallers are kind of big and clunky. They can get grimy at the point of contact between the button and the lock, and that grime will occasionally come off on your fingers when you engage the locks. You look down and there's grime on your fingers, which is annoying when you are about to start playing. Once you're are aware of these things, they're fine. 

Dunlops

Pros: Lower weight and profile than Schallers, and generally a sleeker design than the utilitarian Schallers. The strap button can be installed traditionally, or countersunk into the guitar flush with the surface for a sleek, elegant aesthetic.  Installing the tension clip on the strap side can be tricky. But once it's on, the strap side isn't coming off like it might with Schallers.

Cons: You have to be sure they actually lock when you snap them on. They can sometimes fool you, and if they're not locked, the guitar will fall. So once you engage them, pull on the strap a few times and make sure it's locked. Once you're in that habit, it's trivial and second nature.  I have heard in the old days (70s and 80s -- long before I ever used them) that they could spontaneously 'let loose.'  I have them on several guitars, and I have NEVER experienced that, and frankly, I don't believe it. I think if that happened, it was either because -- like I mentioned -- they either weren't truly locked in the first place, or, perhaps the original ones had a design flaw which was subsequently fixed.