Push through signage is a kind of sign that lights up. It has letters or pictures cut out of a material like acrylic or metal. The light shines through these cut-outs from behind, making a glow around the letters or pictures. This makes the sign easy to see both day and night.
Indoor signs are used inside buildings to help people find their way or show a company's logo. Outdoor signs are made to handle weather and other outside factors, giving information or advertising businesses outside.