Lowboy
A lowboy is a short refrigerator or freezer built to fit under a counter, so the top becomes work space. In a food truck, lowboys keep cold storage at the line without the height of a reach-in.
Size difference is the point. A True TUC-27-HC undercounter refrigerator is 29-3/4 inches tall and 27-5/8 wide, while a True T-23-HC one-door reach-in is 78-3/8 inches tall. Both draw about 2 amps at 115 volts.
Some lowboys are built as refrigerated chef bases that hold a griddle on top. Check the spec sheet for top load ratings before you set cooking equipment on one. Add undercounter units in the layout maker and read the food truck equipment list for more sizes.