OK, so these are actually great. I didn't know what to expect, but these are really nice.
I manage apartment buildings, so have 15 keys plus a Nitecore Tube flashlight and a Gerber mini pry bar on one keychain, and nine keys plus a Ghost mini flashlight and a mini Swiss army knife on another keychain. That's a heavy set of keys, and this device holds the two bunches together.
It's been great. Needless to say, I'm pulling out my keys and using them dozens of times a day. This device secures them really well. Plus the quality is top notch. Really well made.
Previously, I had been using those little magnetic key quick releases that dropped here on Massdrop a while back. The little teeny ones with the super strong magnets.
Well, compared to this spring loaded one, those magnetic ones are bunk.
First off, the release weight of the magnets is significantly lighter than this model. While it holds OK, the magnets just don't feel secure. This one feels much more secure. No fears at all.
But the biggest flaw of the magnetic models, though, is that once the two halves are separated, they will instantly stick to anything on your keychain that is not an aluminum key.
That means each half will suck onto your mini pry bar, or keyring, or sub keyrings. And this will happen every time.
Which means every time you want to reattach the magnets, you have to peel each magnetic piece from whatever it's stuck to (that's 2 pieces stuck to 2 different surfaces) and keep them free and clear amidst your myriad of keys before you can reattach them again.
Try this a handful of times each day, and you'll be done with those magnets.
So this Kappa one is the way to go, IMO. Once these drop again, I'm in for a few more.