Semiautomatic vertical feed build kit for the STEN Mk5. This will allow you to move the magazine well for vertical feeding. You will need this kit, one of our tubes (MK5SAT), and an original Mk5 parts kit in order to build a legal semi automatic firearm. You will need to move the ejection slot on your original magazine housing. This kit includes the following high quality American made parts: a semi-auto bolt, cocking handle, standard AR-15 firing pin, roll pin, firing pin spring, bolt stop, guide rods, rod retainer, 2 sets of springs, and assembly instructions. Two small parts need to be welded together for assembly. Design is based on our ATF approved Mk3 model. Other US made parts may be needed to be compliant with GCA 18 U.S.C. 922r.