Biconvex Lens Set, Pop-Tech Glass Lens Bi-Convex 34mm Diameter 45mm Focal Length Lens for DIY Google Cardboard VR High Quality Biconvex Lenses for better 3D experience Diameter: 34mm Focal Length: 45mm Great to use for DIY Google Cardboard VR Project Package includes 2 pair of Biconvex Lens