The United Kingdom is the world's first country to achieve the integration of sound reduction equipment in light weapons and the distribution of use. Such as the previous MK2(S) equipped with MG(D)3748 sound reduction barrel and MK6 equipped with Type 6 sound reduction barrel, there is also SOE (Special Operations Executive, Special Operations Executive) own integration of CISA sound reduction barrel can only single-shot sound reduction MK2, but because the barrel length of 57 cm, so it is quite impractical.

But in the exile of the Polish engineers to improve its length reduced, diameter increased, and then installed on the MK2 when the effect is very good, loved by SOE officers and SAS team members. The improved sound reduction cylinder is called Welsilencer, the initial "Wel" refers to SOE's workshop in Welwyn (now Welwyn Garden City), which is dedicated to SOE's ninth branch for the production of special weapons and equipment. As long as the products are developed and designed here, the initials "Wel" will be added at the beginning of the name. For example, "Wel "rod (Welrod pistol) for sound reduction pistols and "Wel "bike (Welbike) for paratrooper folding motorcycles. If SOE officers are James Bond, then the ninth branch in Welling can be said to be the Q department that provides all kinds of magical equipment.

This configuration for the BSA assembly of the STEN Mk. 2 submachine gun modified Welsilencer and the installation of Commando Grip no butt sound reduction submachine gun settings, would like to reproduce the appearance of the SOE officers with guns during the war.