A printable treadmill key with an embedded magnet (see below) that allows you to power your treadmill without using a wristband key.

Requires a 20mm x 5.1mm (0.78" x 0.2") magnet (for example: https://a.co/d/apZZkp2 ).

Works with any treadmill that uses a magnetic key and has a ~20mm or greater circular recess  or area for a key. (Pro Form and Lifetime seem to be compatible, for others, YMMV! Try it with a spare neodymium magnet first!)

Be sure to add a pause at the layer just before the magnet. You'll need to either glue in the magnet, or if your printbed is magnetic that should suffice, as the magnet will stick to it and stay in place so it doesn't get caught on your nozzle.

Recommend printing in two colors - add a color change pause for the design on the top so that it pops!

Let the print cool down completely before removing from the heatbed otherwise the bottom will warp due to the magnet's force and weight.

CAUTION: I DO NOT RECOMMEND USING THIS MODEL. IT IS A SAFETY HAZARD. PRINT AND USE ONLY AT YOUR OWN RISK. I AM NOT RESPONSIBLE FOR ANY HARM, INJURY, OR ACCIDENT OF ANY KIND THAT MAY RESULT FROM THE USE OF THIS MODEL.