The Somfy Sunis WireFree II io radio brightness sensor continuously measures the current strength of the sun's rays indoors or outdoors. The Somfy wireless brightness sensor communicates with your existing Somfy smart home control Premium or Basic thanks to its integrated wireless connection. The Somfy Sunis WireFree II io radio brightness sensor enables automatic brightness-dependent control of roller shutters, venetian blinds and awnings: for example, your roller shutters close automatically in summer as soon as a brightness value set by you is reached, preventing your living space from heating up unnecessarily.