High quality powder coated .040 thickness aluminum to prevent rusting. Digitally printed vinyl for numerous design options. Four color process, eco-friendly, weather, fade and abrasion resistant UV ink. Suitable for indoor or outdoor use with an average life expectancy is 10+ years. One size available with a Caution Yellow Background: 4" x 4" (Diamond). This is the same size as a "Drink Coaster". Please note that the signs does not included mounting holes. You have the option to request predrilled holes for extra $1.00.