Use the Yak-Power Power Pack with Integrated USB Charging to bring power to your kayak and integrated 12-volt accessories. The compact waterproof design holds up to three 7Ah batteries or two 12Ah batteries (not included) and features a built-in master power switch and integrated, external dual-USB charging port (5 volts; 4.2 amps). Adjustable slide track and strap secure batteries in place. Built in booted, watertight fuse holder with 15-amp fuse. Includes battery charger. Compatible with Power Ports (YP-PM C48S, YP-PM C96S, or YP-PMC 144S), Power Panel switching system (YP-RPSR) and Power Plug (YP-SAE4). Warning: All Yak-Power plug-and-play accessories are specifically designed to work together while maintaining the correct battery polarity throughout the entire Yak-Power system. Use of other connections or splicing other connectors into the Yak-Power system may cause damage to the system or to the accessories connected to the system and void your warranty. CAUTION: Always pay attention to the actual wire colors of all Yak-Power accessory cables to ensure that the Red (+) wire is always connecting to the Red (+) wire on the connector into which it is being plugged. Type: Battery Boxes.