Giant precision plano-convex glass lens is 98mm in diameter. This very high quality PCX lens has one flat side and one outward curved face. The edge is about 2mm thick and about 23mm at the thickest. It has a positive focal length and is used to magnify. These were made for Mitsubishi large screen projection TV's and are absolutely flawless. Use for thousands of precision optical applications or just to magnify tiny objects. Brand New!