This camera differs from the standard Start (1) camera for the word "Start 2" engraved on the body and for the absence of the shutter button on the lens.
I believe it is an intermediate project. In fact, the needle of the exposure meter has not yet been inserted into the pentaprism.
Body: prototype n. 60000003
Lens: Helios 44 - 5.6 cm - f. 1.2
Prototype n. 00005
Body made in 1960