The Special B was one of N&G's most popular models, some 2000 being made. It was made in four regular sizes (others to order): quarter-plate, 4" x 5" and half-plate. A 5 ½" x 3 ½" two focus model was advertised from 1906. Two versions exist, a two focus model having a convertible lens of two similar components and a three focus model with dissimilar front and rear groups.

Production of the three focus model continued until the mid 1900s, the two focus model until around World War I. By then the fashion for detective cameras had passed.

Several minor variations exist:

• The original circular spirit level was replaced by a 'T' level c. 1896.
• Around 1900 the name of the lens changed from Zeiss Satz-Anastigmat VIIa to Zeiss Protar VIIa.
• In 1903 bayonet lens mounts were fitted.

When using the combined or back lens component the changing box is placed towards the front of the chamber. When the 'front' lens is used it replaces the back lens (i.e. fits behind the shutter), and a frame is placed between the changing box and the front of the chamber. This gives extra extension for the longer focus lens.

The usual serial number prefix for a Special B is SB. The quarter-plate example with an index of B is an early model produced before the index changed to SB.

The price of the quarter-plate model was £22.10.0, the 5" x 4" cost £27.10.0.