Stereo box means an unknown brand. Dated in the 80s and 90s. Most likely it is an accessory to a medical microscope or a camera slit lamp photograph of the eye. The advantage of this display is that through prisms, left and right image can be changed to avoid the pseudo display. It was not necessary to cut the result of the camera. Batteries can be placed in the back of the display for lighting. The holder has some oxidation damage caused by old batteries. This must be repaired. Optically, the display is good and very solid. The sharpness of the lens is not adjustable. The housing is made of cast aluminum. The display comes in a box without instructions.
