This Emergency Lighting Test Key Set contains 7 keys and a handy lanyard, specifically for testing emergency lighting systems. Really handy and essential test keys for electricians, fire, security engineers, maintenance staff, and end users who need to be able to carry out monthly/annual testing. These keys will fit most of the test switches that you will come across - Click, Nexus, Eaton, Knightsbridge, Schneider, Legrand, MK, These keys are essential tools for conducting routine tests and maintenance of emergency lighting systems in various settings such as commercial buildings, offices, and industrial facilities.