Installs easily in a 1-1/4" hole to provide a positively isolated battery feed through terminal connection. Can also be indexed using the two flat sides by drilling a 1-1/8" hole and file fitting the rounded part of the terminal. Two 3/8"-16 brass stud terminals, 5/8" long where terminals can be stacked up to 1/4". Use to run power safely through a firewall or other panel for easy access to energize accessories. The conduit style metal lock nut ensures that the feed thru is securely mounted in the toughest conditions.