Usage Tips:[Be applicable]For safely running power through firewalls or other panels with easy access to accessories. [Installation Notes]A 1-1/4inch hole is required for easy installation. Mounting hole size: 1.25 inches. Stud: 3/8inch. [Installation function]These handy connectors allow you to route the battery cable through the firewall the right way. Use heavy duty 3/8inch x 16inch (9.525mmx1.5mm) brass terminals. Batteries that easily fit in 1-1/4inch holes, provide active isolation via terminal connections. Connectors are used to easily connect power and ground. Conduit style metal lock nut ensures safe installation in the harshest conditions. Note: Installation guide not included, we strongly recommend you seek professional installation. Please check as much as possible to make sure the item is what you need. Tips: The product may be updated constantly ,Due To Different Batches, The Actual Product May Have Slight Differences Or Color Differences, Which Does Not Affect Use Color: black/red Material: Copper + Plastic Package Contents: 1 x bulkhead cable connector Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.