M42 MOUNT SPIRAL: HELIOS-44(M39), 44-2(M42), 44M(M42), 44M-6(M42) 44M-7(M42) 58mm/F2 and Carl Zeiss Jena BIOTAR 58mm/F2(M42)

https://spiral-m42.blogspot.com/2010/12/helios-44m39-44mm42-44m6m42-58mmf2-and.html