WindyNation Solar Panel PV MC4 Connector In-Line Fuse Holder w/ Fuse 30A Each unit includes 1pc MC4 Fuse Holder + 1pc Fuse. For example, the 10pcs option includes 10pcs MC4 Fuse Holder + 10pcs Fuse. Compatible with all MC4 Connectors. Simply install fuse holder at any MC4 junction in your wiring system. Water and weather proof. IP67 rated. 10-amp, 15-amp, 20-amp, and 30-amp fuse options available Changing fuses is fast and easy. Simply unscrew the MC4 Fuse Holder, remove the old fuse, insert the new fuse, and screw the MC4 Fuse Holder shut.