The theft of light bulbs was often a concern. Some effort to reduce this loss resulted in the use of special bases, the use of odd voltages, the etching of the customers name on the bulb, devices that prevented lamp removal without breakage and bulb guards. In the mid 1920s the General Electric Company manufactured a locking socket that was quite effective. In that case one inserted the lamp into the socket and then removed a key that locked the lamp in the socket. The lamp would then turn freely in either direction and removal was not possible. Breakage would not occur.