 Subsequent variants allowed further increase in the bomb load and the maximum size of bombs carried, with external bomb racks.The state-of-the art "Lotfernrohr 7" gyroscoping bomb sight fitted to the Heinkel allowed for reasonable accuracy, for a level bomber.The main versions of the He 111 in use were the Jumo engined H-1, H-2 and H-3 and the DB 601 powered P-2 and P-4.