OK, i have to admit i've no idea whether this is actually a Model 3. The bit after "Model no." on the end of the slide is totally obliterated and i can only make a random guess. I'm virtually certain it's not a model 4, and the scale arrangement is slightly different than the Model 2, so unless it's a different version, i'm pretty sure it's not one of those, either. Anyway, it's another nice old Magnesium rule. This one seems to have survived a little better than some, though it does look like someone assaulted it with red and blue markers. Not to brag or anything, but i bought this for $2.00.