Abstract: A structure for reflecting visible light or near visible light, wherein the structure is formed of a low dielectric constant material having an external surface comprising an electrically conductive layer of material which has an array of slots therein so as to be substantially transparent to microwave radiation of a predetermined wavelength which will impinge upon the structure during use, while being reflective to light.

Abstract: To facilitate installation of cables through bulkheads and other surfaces and to provide electrical protection to apparatus connected to such cables, an assembly comprising electrically conductive blocks (6) clamped in a frame (2) is provided. The mounting blocks 6, each formed of two parts for fitting round a continuous cable length include ribs (11) adapted to grip the sleeving of the cable and an extended rib (10) for contacting screening of the cable. In use, the frame (2) is welded to a bulkhead or other conductive (earthed) element. A section of insulation is removed from the cable and on clamping of the assembly the blocks (6) are compressed together forcing ribs 10 to contact respective screens. Thus any induced electro-magnetic pulses on the cable screens are provided with a low-resistance leakage path.