The grid is 1 degree x 1 degree in 5 minute increments. Attached is some K&E literature.
You can use either a distant target or use another lens to create an infinity target within inches of the objective to accomplish the same thing. See photo.
Hello Buck;
Just a couple of comments on the double collimator. These are very useful to optics geeks. If you decide to sell or trade them, find an optics nut.
They are 6x, I think 30 mm objective.
If you want to try to use them as binoculars to measure angles, place your left hand at the front of the tube, assuming you right handed, and grasp the eyepiece with the right hand. To keep a target centered, move your right hand toward the target; you move the eyepiece toward the target, not the objective end.
The collimator is fixed focus, infinity, but has a great depth of field. The eyepiece only focuses the reticle, not the image.
A collimator is generally made to work the other way around, most do not have eyepieces. Look into the objectives with a pair of binoculars. The binocular will always focus at infinity whether you are 1 inch away or 10 feet. The grid will measure the same 5 minutes between lines at any distance, as you back away, the lines will appear to get larger but the angle remains constant. When the center of the grid is in the center of the bino field of view, the optical axis of both are about parallel, but not necessarily in line with each other. This is what makes a collimator so useful. Even if looking into the very edge of the lens, if the reticles match, they are parallel to each other and do not have to be on the same line.