I designed this collection of musical notes keychains / key tags using SVG files from https://www.svged.com/.
At 100% scale, all keychains measure 2.0mm high. The keychain hole's outside diameter is 8mm and inside diameter is 4mm. The width of the keychain hole ring is 2mm.
There are two sets of keychains, one without any back layer/bottom layer, and one with a back/bottom layer for added support/durability. For all keychains with bottom layers, the bottom layer measures 1.4mm high.
Enabling ironing on top surfaces for best results. If printing with bottom layers, color change occurs after layer height of 1.4mm.
Pictured keychains printed with 4.0mm nozzle, ironing all top surfaces, 2.00mm layer height, 25% infill, color change at layer 1.6mm for bottom layer keychains, white and black PETG.