Abstract: An avionics housing has electrical equipment within it connected to an electrical connector by means of a flexi-rigid assembly having multiple conductive tracks extending side-by-side on an insulating layer. Radio frequency interference between the connector and the equipment is reduced by forming the flexi-rigid assembly into one or more loops about a ferrite block which absorbs radio frequency on the conductive tracks. The housing may have several blocks of different materials which absorb radiation of different frequency ranges. Additionally, the assembly may be wound about a plastics block to form an air-cored coil for absorbing higher frequencies. Where only higher frequencies are to be absorbed, the air-cored coil may take the place of the ferrite block. The flexi-rigid assembly also includes a capacitor assembly in the form of two conductive layers extending across opposite side of the conductor tracks and insulated therefrom.