"With the 17th edition in full swing, RCBOs are being used more and more. These Crabtree RCBOs are looking expensive compared to the opposition now. I've also had some faulty ones. And only available as type C. For these reasons I don't choose Crabtree as replacement boards and only use these RCBOs to fit into existing installations. Buy two in case one's faulty and send the other back when you know you don't need it. Performance is good because trip times are always low."