Bought to replace standard fuses, not to protect electronics. I tested it and it responded too slowly. The 3A fuse in series with this 1.8A resettable fuse blew long before it could react. I actually tried higher rating fuses, 24VAC, and it didn't work. Well, I wish there was such a device. I gave it 1 star for others to read and know. Otherwise it could be a good resettable fuse.