Meter seals are used with electric or gas or water meters and usually molded in polycarbonate. The transparent body of the seal means that the locking mechanism is visible, and can provide clear indication of tampering. 

Meter seals can withstand exposure to sunlight and extreme weather, and a wide range of temperatures. Designed for only a single use, they are destroyed when removed. Some meter seals contain components which glow under ultraviolet light, allowing the seal to be easily located in darkness.