This is a standard military lettering style stencil in 28pt font. -Edit- The 28pt stencil is way too small to print reliably on my machine. I have uploaded a 48pt stencil as well, which works a lot better. If you have your profile tuned to give really high x and y resolution, you might be able to get the original stencil to work. If not, try the 48pt model.

Print it out. Use high infill to get a stiff stencil.