A lowboy is a semi-trailer with two drops in deck height: one right after the gooseneck and one right before the wheels. This allows the deck to be extremely low compared with other trailers. It offers the ability to carry legal loads up to 12 ft (3.66 m) tall, which other trailers cannot. Lowboys are used to haul heavy equipment such as bulldozers, industrial equipment etc.
Removable Gooseneck (RGN) trailers give you the opportunity to move those same tall products, but also give you the ability to load large pieces of equipment onto the trailer by driving them on. The front of the trailer is detachable, which allows the trailer to drop to the ground and create its own ramp.