I am doing a VAV controls upgrade, and they are all TITUS boxes with parallel fan and reheat. All the box sizes range from 6" to 12"/14". A majority of the boxes say the size is 02, 03, and 05 on the cover. Normally it would say the size of the box diameter in inches. Does anybody know what the those numbers coordinate to in inches? So far I've been doing rough estimates with a tape measure and just from looking. Its hard since all the supply ducting has thick insulation on the outside.