Like Mike says, if you are referring to the raised carpeted platform (most often seen in front of the fridge) when the slide-out is out, that is the wheel well.
Unlike many other class C manufactures, the Phoenix Cruiser main floor accommodates protruding wheel wells. This was done to lower the floor (and house) for a lower center of gravity which improves ease of drivability, has one less step to get inside from the entry door, and has only a 2" floor-transition between the cab up front and the house behind it. That small transition is nice when turning the passenger seat around to use in the house. Phoenix Cruiser owners find the inconvenience of the wheel wells to be a small price to pay to gain those benefits. Some PCs like our 2007 2350 without a slide-out, the protruding wheel wells are under cabinets, so we never see them.
