Check the listing for details. Antique KLETT BIO Colorimeter Microscope. Listed at 39.95 USD. This is an antique Klett Bio Colorimeter Microscope. Probably made around 1925-1930. I'm not sure what it was designed to do, but it has an interesting "steampunk" look about it. Although it works, it has some condition issues: 1. It is missing one of the lenses (4th photo), and the rack and pinion focusing adjustment does not work on that side. The little circular stage slides up and down, but the pinion gear inside it is apparently broken and does not engage with the rack for fine focusing. The other side works fine. 2. The paper colorimeter chart in the window in the base does not move when you try to turn the black plastic knob (5th photo). 3. The glass platform on top of the base is missing a small screw on one side (3rd photo). 4. The electric lamp socket and cord have been replaced. The bulb seems to be in good condition and works fine. This item is offered at a discount, because of the condition issues.