This is a 3D printed Cart Keychain. The idea is to attach this to your keychain and stick it in a shopping cart instead of a quarter. I measured it up to match a NIS 5 Shekel Coin, which is similar to most international "standards".

The first version was designed in Tinkercad, and I printed it successfully (and it works in the cart very well)

But, The second one is made in Fusion 360, I improved the design and added a filet. Currently, it's extruded till 1.3 mm, but should be between 2.4 to 2.6 to work properly.

Key V5, is the corrected version, I made it a little longer, moved the keyhole in a bit more, and fixed the filet. This version hasn't been printed yet.