Check the listing for details. American Optical Microscope Phase Ring Slider 40x Ring, Iris Diaphragm & Carrier. Condition: Used. Listed at 45.00 USD. American Optical ( AO ) Phase Contrast Microscope Phase Ring Slider with AO 1259 40x IWD Ring, Iris Diaphragm, & A1206 Carrier There's a glass lens in the slider under the phase ringThere are ring centering controls in the slider.Diaphragm range is about 2 mm to about 28 mmThe dovetail O.D. is 47.2 mm Check the photos and description carefully to see exactly what you're getting. If you have question please ask them before bidding. I don't accept returns except as noted. ------------------------------------------------------------ The shipping cost shown includes shipping charges, packing materials, and insurance. A delivery confirmation fee may also be added for expensive items. An adult signature may be required. There's a FedEx 1-2 day option if you're in a hurry. I'll be listing a number of lenses, lighting, camera port options, and other accessories for Zeiss, Olympus, Mitutoyo, and other microscopes, as well as electrical test equipment and components over the next months. Click "Save Seller" just below and to the right of this description, for easy access to may newest listings. 0.44 4.5 x 3 x 1.25 ( 100915 )