My Unscientific Spectra Test

We just call them "key rings" in the UK and they are a cheap source of making connections.

Some supplied with key labels (tags) are soft wire and couldn't pull the skin off a rice pudding. You can stretch them by slipping them on a finger and easily pull them apart and straighten the wire.

The ones as Fred describes are incredible strong and come in different sizes - not only diameter of the ring but diameter of the wire. I wouldn't hesitate to use them but only after testing them.

As Fred describes - they need to be 3 turns but also no sharp edges. Some of them aren't very well formed and are made so that where the turns touch each other - the faces are flattened. This is fine as long as the finished cross section doesn't end up as a sharp oval.

The can be heavy though at the aeroplane end - quite a few commercial handles came with these rings fitted.

This is a more recent one



but the ubiquitous Keil Kraft metal handle with the spike came with them as well. We all used those for combat models in the sixties.

All connectors have their limits and it is best practice to test everything.