XPFD3 said:It usually equates to the number seats in the crew cab and in photos it is usually visible in the amount of space between the rear edge of the crew cab doors and the back of the cab. When departments add EMS compartments and seating for 6 or more firefighters it requires extra cab length. MFD = MEDIUM FOUR DOOR. XMFD is a longer version. LFD = LONG FOUR DOOR. XLFD is a longer version. Some apparatus manufacturers show seating layouts for their various cab lengths on their websites.
Hope this helps.