Keep your announcement or listing secure behind acrylic, shatter-resistant hinged doors that come equipped with built-in disc tumbler locks. Letter panel has a precision grooves for easy letter insertion for a long-lasting background for your messages. Interior case depth is 1-5/16". Letterboard includes two keys, a built-in mounting system and set of vinyl 3/4" letters, numbers and characters. For outdoor usage, enclosed board has a weather-resistant backing and durable satin aluminum framing. Water-resistant design is perfect for outdoor placement under an awning or overhang. Letterboard is ventilated to prevent moisture buildup inside.