From June of 1941 until August of 1945, the Studebaker Corp. at South Bend, Indiana, produced almost 200,000 of their legendary 2½-ton US6.
The truck came in 13 variations, as 6x6 and 6x4, with short (148in.) and long (162in., shown here) wheelbase, with and w/o winch, as cargo and dump truck and as tractor.
The Soviet Union received almost the complete 6x6 production of 105,000 as well as the majority of the 90,000 6x4 produced.
The "Studer", as they called it, became the reliable workhorse of the Red Army and contributed much to the fast late-war advances.

Still in August 1941, the first 82mm rocket launcher was produced, the BM-8-36 on the ZIS-6 chassis.
The BM-8 launcher differed from the better known BM-13 launcher in that it had a complete 360 degrees traverse allowing the launch ractangular to the vehicle direction and hence omitting the unsual windshield protection.
As more and more foreign chassis became available the Ford-Marmon 1½-ton 4x4 and the Chevrolet 1½-ton 4x4 began to replace the ZIS-6 as platform.

Note
The vehicle shown here is part of a Guards Mortar unit.
The vehicle on the left and above comes with the rear ground stabilizers installed and the fourty-eight 82mm rockets loaded, in other words... it's ready to fire!
The vehicle below has the rocket launcher turned into a typical travelling position.
The truck is of the early U3 version, with the wipers still fixed to the cab, the fuel tank on their usual place and the firm logo showing on the brushguard.