Fits most gu10s the gu10 fly leads is a 240 volt mains power gu10 spotlight holder which any standard size gu10 bulb will fit flush into get extra peace of mind it comes with a class 2 double insulated cable giving you flexbility quality and reliability when upgrading light fittings in older properties plus the 130mm fire rated wiring case will stop the wires from burning out so you will be perfectly safe switching from low voltage to 240 volt easy to install this fly lead is easy to