Switched models were equipped with a flat paddle that might or might not have the company's logo impressed in it.Because the electric market was still small, not a lot of these Lange sockets were made and they are somewhat of a rarity today.
The first real challenge to Edison's hegemony came with the inauguration of Westinghouse's AC (alternating current) system in 1886.
The Thompson-Houston Co., a supplier to Westinghouse, introduced the seminal socket for AC, which featured a distinctive cylindrical shell design.
By around 1900, most of the other manufacturers, which numbered about 20 at this point, had adopted the new switch design and shell shape, bringing out their own versions with their name imprinted on the switch paddle.
The main producers at this point were General Electric (GECo), Perkins, Paiste and Bryant (who had taken over Westinghouse’s socket production in 1890).
Of course, bulbs from one system would not fit the sockets of any other system and, while every company claimed their method was superior, their motive for exclusivity was arguably to keep their customers captive.