The blue spot tools mains tester screwdriver 4 x 100mm mains tester screwdriver is manufactured with a fully insulated plastic handle and blade sheath for added safety. Circuit tester conforming to CE and GS standards A neon indicator lamp located inside the handle illuminates when the live part of an electrical circuit is detected Fully insulated plastic handle and blade sheath for added safety Suitable for use on circuits where the current does not exceed 250V Size: 4mm x 100mm To operate touch metal top and test live parts