Comus mcs 138 alum mag contact switch magnet and l bracket armoured cable comus mcs 138 1 this loop type normally open magnetic contact switch comes with an l shaped bracket and is designed for use as an overhead door contact switch with a cast aluminium housing and 22 armoured cable that make it suitable for use in harsh environments in both commercial and industrial applications a matching magnet is also supplied comus mcs 138 1 aluminium switch magnet l bracket set with armoured c