That is, only one side of the effect is opaque, the reverse side can not see the effect of the product (usually used in the TV wall, lobby wall, corridor aisle background wall). Double-sided effect: opaque or transparent. That is, the effect of the product can be seen on both the front and back of the product. Generally, the back side is an engraved surface, and the front effect is generally a glossy surface (usually adopting a self-screening, porch, partition, door and window).