Its main purpose was to produce smoke for cover and through high trajectory and HE shell, engage targets "immune to small arms fire".

Due to its small size, and for simplicity, the mortar had no forward strut or bipod like larger designs needed.

The original design had a large base plate and sights for aiming which used spirit levels.

As the design matured, the baseplate became smaller and the sights were omitted; aiming was by eye and relied on the firer's judgment and experience.

With such a short barrel, the typical firing method where the bomb was dropped down the tube and a pin in the base of the barrel struck the detonator in the tail of the bomb would not work, so firing was by a small trigger mechanism at the breech.