Had one for 2 years, when they first came out. They had 2 diodes then. sent mine back because of leaks. Sent me the new version,broke in 2 months. sent me another ,that broke. Sent me a new unite. It has been working now for 6 months without a problem. when working correctly, second to none. It will not find Gold chains. You can take a gold chain and rub it on the coil. nothing