The Model B was chambered in 9mm Luger and was intended for export outside of Spain, being produced for 52 years from 1931 to 1983 when replaced by the similar "Super" series.

Postwar, the West German Landespolizei made use of Model Bs until 1963, and small lots were also purchased by Israel, Peru, South Africa, and Spain for military or police use.

When the weapon is discharged, the gases produced from the cartridge cause enough force for the link to cam the barrel down and push the slide back.

Aesthetically, the Model B is similar to the later 1911A1, thus sharing features like the trigger guard relief cuts, larger ejection port, and arched backstrap.

The Model B has several key functional differences: it lacks the grip-mounted safety present on the 1911, and the backstrap is non-removable and does not feature the mainspring housing like the Colt does.

There is no slide stop plunger tube on the frame, which on the Colt results in a small opening hidden behind the grips.

The later Model B Super carries many of the same external functions and dimensions, but utilizes different mechanical features, the biggest being a linkless camming barrel similar to the Browning Hi-Power.