Window hygrometer for mounting outside on the window frame or reveal. The small pivot arm allows the devices to be folded away, for example, to open a window which opens outwards. Case, pivot arm & mount made from zinc, therefore rust-free & weather-proof. With domed glass cover over face. Scale from 0 to 100% humidity. Diameter 11 cm, thickness 4.5 cm, projection 7.5 cm, weight 180 g.