Our engraved elevator signs for indoors are made of 60 mil thick plastic and feature precision-engraved characters on the smooth acrylic plate. On the other hand, the outdoor engraved elevator signs are made of 60 mil thick weather-resistant plastic. These have precision-engraved characters on a textured outdoor-rated acrylic plate. Both indoor and outdoor engraved signs are loaded with UV inhibitors. The UV inhibitors prevent fading on indoor signs for up to 5 years and 20 years in sunlight for outdoor signs.