This model is from How._. from Printables.com, added here for reference, with added print files for Bamboo Printers.

After remixing the Number Stencil (https://www.printables.com/model/770316-number-stencil) thought of expanding the stencil for Alphabets and Characters, with its useful adaptations to ease its use. 

Best Scale up model in slicer for whiteboards surfaces to allow bigger marker tip to stencil.

1. Alignment grids for stencil

Had updated the original idea of holes for alignment to crosshairs. 

2. Included notch for easy lifting and positioning 

Simple and it works.

Printing Tip: 

If your numberings/characters are getting pealed off during first layer; increase your lifting height to clear your nozzle head from the laid filament in the Slicer (Printing Setting - Extruder - Lift Height). Hope this helps!