XYZ stickers for marking the axes of inertial sensors and IMUs on objects. The stickers are intended to be printed in the sticker books sold by moo.com. Each page contains 6 stickers, one for each orientation of the axes. The axes follow the right-hand rule and the common 'RGB = XYZ' colour convention where: Red is X, Green is Y and Z is Blue.
See the original post on the x-io website for more information.