International standard interface 4/5 inch 1/36 inch. Diameter about 20.3 0.705MM. If you have any problems or concerns whatever with your order or products, please message us and give us a chance to assist you before you leave any feedback. We believe we can produce a positive outcome to any situation and will work hard to earn your praise.This item is in the category "Business & Industrial\Healthcare, Lab & Dental\Medical/Lab Equipment Attachments & Accessories\Microscope Parts & Accessories\Microscope Objectives". The seller is "captain_2011" and is located in this country: CN. This item can be shipped worldwide.