Blind closure AP W.1 gray. W.1 specification of installation devices. The specification described below must be offered for all installation devices. A uniform brand/type must be used for both surface-mounted and flush-mounted installation devices. The protection class of the program is designed to IP55. Switches must generally be offered as toggle switches. All switches and buttons are printed on the back with a circuit diagram and switching symbols. The surface-mounted housings have the option for rear cable entry with a soft component. Selected brand/type: Berker W.1 or equivalent. Selected brand/type: '___________/___________'.