Attention! Lens Industar-69 has connection thread - M39 but the flange focal distance 27.5 mm, standard distance for m39 lenses is 28.8 mm, so you can`t focus to infinity!
My lens was modernized for flange focal distance 28.8mm and tested on my camera to infinity point focus (see photo)!
That is, you can use this lens with m39 adapter on any mirrorless camera and you can focus to infinity!!!
Also my lens modernized for minimum focusing distance from 0.4m! That is, you can use this lens also as macro lens!