This is a very nice example of a fairly scarce and desirable WWII SMG as manufactured by the Marlin Firearms company for the United Defense Supply Company. This actual SMG was designed and patented by Carl Swebilius founder of the High Standard Firearms company, who in turn had the Marlin Firearms company actually produce the SMG for the UDS company. It was actually designed/developed in 1941 but was not actually produced until 1942, hence the later model number of "UD-42". They were originally intended as a substitute for the Thompson SMG, but by the time they actually got into production, the Thompson/Auto-Ordnance company caught up with their back orders and the intended orders for this SMG never materialized in any sizeable quantity. It is estimated that total production was approximately 15, 000 with a large quantity being used in the Far East and Philippines. They function in a blow-back type operation that uses a 20 round Thompson SMG magazine. There are two unique features of this weapon, one is that it does have a hold-open catch, that holds the bolt open after the last round is fired. The other is that the right side of the weapon has a sliding cocking handle almost identical to the cocking handle on the FN-FAL rifles. The left side of the receiver has full factory markings along with the "UD-42" model number with the right side having the full/and semi-auto markings. It has a fixed front sight with a very interesting rear sight that actually sits on top of a shaft that raise out of the rear of the receiver, which is fully adjustable for windage and elevation. These models appear to be a very robust weapon being machined entirely out of steel with a heavy driving spring inside the rear receiver. It has a vertical walnut front pistol grip mounted under the barrel in front of the magazine well, with a walnut buttstock and steel buttplate. The left side of the buttstock has a small aluminum label affixed to it which reads; "PROPERTY OF CITY OF YORKVILLE, ILL. NO 00054". This SMG is complete with one twenty round Thompson stick magazine and two, twenty round Thompson stick magazines that have been brazed together, which is correct for this weapon. As noted this is a fully transferable, fully automatic SMG that is listed on the ATF Form 4 along with the ATF transfer tax stamp.