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 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. They are made out of reflective material, they reflect bright at night when hit with light.