NOTE!!! TANKS DO NOT COME WITH A SENDING UNIT. IF YOU NEED ONE, WE CAN SUPPLY YOU WITH ONE, WE NEED TO KNOW THE OHM RATING OF YOUR FUEL GAUGE AND YEAR OF YOUR VEHICLE. Please specify a filler option: TOP FILL - STANDARD CAP - Through the bed. Comes with a standard screw on cap at no extra charge. You will need to put some kind of trap door in the bed. TOP FILL - COOL CAP - ($60.00 Upgrade) Through the bed. This is a marine-style, polished aluminum cap, which is flush-mount with the wood. SIDE FILL - Through the driver side fender. Comes with a C-section to C-notch the frame if required