1" aluminum barrel with multi-step baffles on one end. The lens complement consists of a double concave and a plano-convex lens. Both are 10 mm diameter, and are anit-reflection coated. The effective focal length is 28mm. The barrel has a fast-helix, round-grooved thread section. This assembly may have been designed as the objective lens in a photo negative magnifier. It is similar to our #L10779, except that it lacks the flared baffle on one end. Unused.