using only the lens head (M42 mount), of course also M42->SR adapter is used too,
Minolta portable-bellows has been E-mounted already. Rubber band around the lens
gives friction to the aperture ring. There is no click stop installed to this lens head.

If you do not like this rubber thing, you can tighten the 3 screws of lens outer shell
so that the aperture ring becomes a bit stiff to rotate. This might be easier to use.