Kappa Quick Release
This design is identical to (and compatible with) the Beta-QR v2 quick release design. A proprietary "canted coil spring" is used to provide a "snap together" action: two pieces, no moving parts, nothing to break and the spring is replaceable if that's ever needed. The spring is manufactured by a company that specializes in only this type of spring. It's commonly used for electrical and mechanical interconnects on everything from heart implants to military electronics to stuff that flies in space. It should be adequate for your house key.
The mechanism is incredibly simple and robust. Spring failure is extremely rare, but if it does happen, it's not a sudden "unscheduled dissasembly" like with plunger style keychains. If there is an issue with the spring, you'll see it coming and you can easily replace the spring at home. Typically a failure results in the Kappa becoming difficult to separate vs. coming apart unexpectedly. Like everything we make, it's designed for the long haul and easily repaired.
I was constantly frustrated with my keychain and having do deal with the entire thing, when I just wanted to use part of it. Over the course of my life I tried all kinds of different quick release mechanisms and they were either ineffective or fell apart over time. The Kappa QR is a natural extenion of the Beta QRv2 flashlight mechanism. It allows you to reconfigure your keychain with only the items you need, or even combine other items into new configurations that are useful in the varity of situations that life throws at you.
The worst was my car keys swinging around, making noise, and constantly hitting my knee. No more I say! Now I just pop my car key off my keychain, put it into the ignition, and smile with the satisfaction only a finely cratfed and well designed object can bring.
* Split rings (2x 20mm and 2x25mm)
Size1.25" x .5" (without split rings)
weights & materialsC360 Brass (19g)
C145 Copper (20g)
6/4 Titanium (11g)
6061 Aluminum w/ Electroless Nickel (10g)
where it's made