The EMO B-C flash unit was produced and sold by a company owned by Arthur Seibert, the (initially from Leitz) optics engineer behind the PENTAR and COMPLAN lens for Minox cameras, and also the inventor of the Emoskop. The flash unit is similar in design and functionality to one such, made by Minox. It is made from plastic, in grey tones, and uses AG1 flash bulbs.
Using the same type of bulbs (AG1), and the same battery (Mallory/Eveready 504/15v), it has a sync cord which attaches to the Minox camera flash nipple. This allows the user to position the flash in different positions, not necessarily facing straight forward, side or bounce flash lighting is possible.
You may use it with any camera that has a flash shoe installed (obviously you will need to have a sync flash socket on that camera). Flash bulbs are scarce nowadays, but can still be found if you need these, both AG1 White Dot (allegedly for BW film) and AG! Blue Dot (for color film).
Never seemed to me there is any difference between these two models, but probably I wasn’t paying attention enough. They all appear to have the same effect on film, irrespective of its emulsion type.