Bandai uses a convention called grade to describe generally how detailed a given model is. Many models are available in multiple grades, depicting the same fictional machine with the same general appearance, but with different levels of part detail. A High Grade (HG) model for instance will have noticeably less detail than a Master Grade (MG) The models are also different sizes, with the HG being about two inches shorter than the MG. Similarly, a Real Grade (RG) may have just as much if not more detail as a main line Master Grade, but usually have everything contained within the size of a High Grade.