... .high luminous 2.waterproof led signs 3.Three side lighting 4.for both indoor and outdoor install led ... letters , 3d letter sign , backlit letter sign , LED acrylic letter signs have the advantage as following:1. Use superior acrylic board ... be widely used in many places, such as shop signs,hotel signs,hospital signs,school signs ,advertisement, architecture, decoration, exhibition, and lighting, etc. ...