My old automobile battery charger stopped working. I notice that one of the old circular button diodes had failed and the other one was near failure. I ordered theRR050 Rectifier Repair kit from PLP Battery. The kit with two 50A diodes in on part came on the day promised. I installed the new diodes in less than 15 minutes. Bingo! The 50-year old Charger worked again, and a heavy transformer, case and cables were not sent to a landfill. Instead, they are sitting right beside my new charger, which is totally useless if the battery is totally discharged. I'm very happy with the folks at PLP. They delivered for me.