This binding post set (1 Black, 1 Red) is ideal for building your own charging station or as a 12-24volt power access point for DC power applications. They are designed to pass through wooden or metal facias up to 10mm thick (they are insulated and required a 7mm mounting hole). The output terminals have 4mm holes to suit 4mm male banana plugs, the terminal tips can be removed to allow aligator clamp access, the screw on terminal caps are insulated with a hard plastic shell. Rated to around 50amps. Spec: Total length: 33mm Depth: 10mm Mounting hole: 7mm