Customizable Tricolor Card Holder

This is the __three color__ version of my [customisable business card holder](/thing:218124).

To customise this you need to upload two, 150 x 40 pixel, black and white images containing your logo - one for each colour. The logo should be white and the background black. Images will be automatically stretched to fit.

_Note:_ the customiser preview only works when both images are loaded.

When you print it, you need to pause your printer and change the filament color, either manually or usi