Westinghouse Pagoda II Solar LED Post Cap Light for 4 x 4 Wood Posts (Bronze, 6 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 plastic construction will handle the outdoors with ease Bright white LED bulb is powered by the included 600mAh Ni-Cd battery Includes mounting base for installing onto a rail Includes mounting base for installing onto a rail