RV compartment was original for 2 horizontal propane tanks still could be used for that but could also be used battery Box Compartment for bigger lithium lifepo4 bank w/ Vented Door Hatch. Has non locking latches but easily swapped to locking ABS box with vented hatch. Used removed from older RV camper could be a nice base for schoolie build sprinter van build travel trailer off grid solar set up 27x19.5x13.3 at the edges but rounded corners make useable space slightly different