Selector switch head Ø22 3-position spring return Ronis 421E. range of product: Harmony XB4 – device short name: ZB4 – mounting diameter: 22 mm – head type: standard – return: to centre – type of operator: spring return – operator position information: 3 positions +/- 45° – type of keylock: Ronis 421E – key withdrawal position: center.