The J-B Ensign was advertised as the Junior Box in the Ensign trade catalogues of 1931 and 1932 but did not make it into the 1934 edition. The camera was also available through premium schemes such as the John Bull magazine. J-B is also found written as J.B. Given the similarity in the initials of the camera and the magazine it is a possibility that the camera was produced with premium sales through John Bull in mind.

The upright appearance is due to the spools being placed above and below the film plane not, as is usual, close to the lens. Although the position of the spools leads to a larger camera it does away with the need for an inner cradle to hold the film. The same arrangement was used on the Ensign E29 box camera.

Accessories included a portrait attachment and tripod attachment. The price was 8/6 which was considerably cheaper than other Ensign box cameras.