After loading the kid's scooters into the car for the 99th time, I managed to loose the metal button that is spring loaded into the handle bar stem. It releases the handle bars from the platform, and the scooter is surprisingly useless without it!

Fortunately we have two kids, and what one wants the other wants, so I had a spare to model a replacement off. I was delighted to find the 3D printed replacement worked perfectly and has served us well for over a year now.