The Slip Ring Interface boards utilize 4 slip ring wires on each of the two power rails to allow for higher currents. Board also has I2C (4 pins, D, C, 5V, G) and Serial (4 Pins, Tx, Rx, 5V, G) pins broken out. These 8 pins utilize one slip ring wire apiece and can also be used as one wishes.
LEDs can also be installed to provide visual feedback that power is indeed being passed correctly through the slip ring. Their installation is optional.