Anand traders Plano Convex Lens for Telescope Project 100 cm Focal Length Making Kit (50 mm) : Amazon.in: Electronics
StayMax Concave Convex Lens Set Optical Glass Lens for Physics Teaching 2 Pack: Amazon.com: Industrial & Scientific
EISCO High Quality Glass Lenses, Set of Four, Double Convex & Concave Lenses of Dia. 50 mm, Polished, High Quality : Amazon.in: Industrial & Scientific