The wireless and battery-free "Friends of Hue" smart switch offers foolproof control for the entire Philips Hue universe. The switch can be used to control up to 50 Philips Hue lamps and lights simultaneously. Thanks to energy harvesting technology, the Friends of Hue switch generates enough energy to send a wireless command every time it is pressed. This means that no cables or batteries are required and the switch never needs to be recharged.