Westinghouse Pagoda II Solar LED Post Cap Light for 4 x 4 Wood Posts (White, 2 Pack) Interior base measures 3.88" x 3.88", rail adapter interior measures 3.5" x 3.5". Each light measures 5.94" x 5.94" x 4.75" Durable weather resistant construction will handle the outdoors with ease Patented Natural White LED Included with each light is a 600mAh Rechargeable AA Ni-Cd Battery Includes mounting base for installing onto a rail