Approximately 6.5 inches wide and 4 inches tall.
It's not yellow on black, it just looks that way in the picture. It's a die cut decal, just the yellow design (or black or white/silver). It's applied with transfer paper. You take the sticker off the backing paper, leaving it on the transfer paper, and then you apply the transfer paper to the window, peel the transfer paper off the window, leaving just the die cut decal applied to the window. You know the kind. Ask me about it if you have questions. Very cool decal. The White/Silver and Yellow decals are made out of reflective material.