14 x 12 x 30 inch steel toolbox made by Buyers. The Buyers part number is 1703353. This box adds a ton of handy storage space. Great for pots/pans, electrical setups and just general gear that you need access to. 

These are steel and are heavier than the Warhorse mfg’d aluminum side boxes. Also, the door on these buyers boxes isn’t the best shelf-space given the inside of the door doesn’t have a flat platform and the door latch is in the way. Regardless, not a bad way to go if you need the space.

You can also get these on Amazon for ~$300 and add them yourself later.