Nice mounted air-spaced achromatic glass telescope objective. Both elements are coated. Clear lens diameter of 90mm with a focal length of 1000mm (F/11). Front barrel diameter is 100mm (ID) and 105mm (OD), rear barrel is 90mm (ID) and 99mm (OD). Center of the barrel is 117mm diameter. The entire assembly is 57mm long. These are brand new and will make a great scope! Or get 2 for a binocular scope. New
