1" aluminum barrel with multi-step baffles on both ends. The lens complement consists of a double concave and a plano-convex lenses. Both are 10 mm diameter, and are anit-reflection coated. The effective focal length is 29mm. The barrel has a fast-helix spherical grooved thread section. This assembly may have been designed as the objective lens in a photo negative magnifier, as the focal point coincides with the face of the wide flare baffle section on the end of the barrel.