The pallet contour Q4, Q5, Q6 & Q7 are other definitions for the IATA Contours L, X, A & D that be used for contour to build up a pallet for main deck. 

E.G:

ULD Type	Base			IATA Contour	Pallet Contour
	Length	Width	Height
PMC	317.5 cm	243.8 cm	243.8 cm	X	Q5

In this case the last letter of the ULD Type  (PMC) isnot leading as contour, but the IATA contour X that gives the contour how the pallet must be build up for main deck

Contours

IATA Contour	Pallet Contour	Aircraft Deck	Maximum Height		Base Height
			cm	Inch	cm	Inch
L	Q4	Main Deck	294.6	116	243.8	96
X	Q5	Main Deck	299.7	118	243.8	96
A	Q6	Main Deck	243.8	96	243.8	96
D	Q7	Main Deck	299.7	118	243.8	96

Pallet Contours