For the Leica T bayonet, an M42-L / T adapter is available. HELIOS-44-2 2/58 has a diaphragm preset ring. With it, you can select one of the fixed values: F / 2, 2.8, 4, 5.6, 8, 11, 16.
There are wet plate, dry plate, detective, subminis, stereo and more. It looks like it could be set up for stereo since the holes for a septum are there.
See photos of the notches in the front and the holes in the rear; top and bottom.
The lens is tested and works properly. There is some dust specs on the inner lens.
The bellows have a few markings and holes in them. They would need to be replaced if you wanted to use this camera. There is a white piece or cardboard attached/ glued on. I'm not positive if this is removable or what (see photos) I listed this for parts or repair mainly due to the bellows.