Google Cardboard 45mm Focal Length Virtual Reality Headset - With Free NFC Tag & Headstrap (Brown) Complete Kit with NFC, Head-strap, pre-built and assembled in seconds. The perfect solution for Virtual Reality on a budget! Easy to assemble. With Printed Instructions and easy to follow numbered tabs. Biconvex lenses 25mm in diameter and Focal length 45mm (exact Google Cardboard specification) Made from High Quality, Hard-Wearing Cardboard