Comus mcs 139 alum mag contact switch magnet and l bracket armoured cable comus mcs 139 1 a low cost loop type normally open magnetic contact switch that features an extruded aluminium case and 22 armoured cable making it suitable for use in harsh conditions supplied with an l shaped bracket and matching magnet making the switch suitable for use as an overhead door contact comus mcs 139 1 aluminium switch magnet l bracket set with armoured cable