At 100% scale, the keychain is roughly 50mm length and width (~2 inches), and 2.6mm height/depth. The bottom black part is 2mm high, and the top white part is 0.6mm high.

The keychain outside diameter is 8mm and inside diameter is 4mm. The width of the keychain hole ring is 2mm.

Enabling ironing on top surfaces for best results.
Color change occurs after layer height of 2.0mm.

Pictured keychains printed with 4.0mm nozzle, ironing all top surfaces, 2.0mm layer height, 25% infill, color change at layer 2.2mm, white and black PETG.