Isri Seats are a specialist seat manufacturer supplying OME and aftermarket seat options for Trucks, Buses, Coaches and Earth-moving equipment. They come standard in Volvos and Isuzu trucks and are supplied as driver's seats in other various original equipment. The 6000 and 6500 identifies the suspension base. Please note your seat may come with no headrest and this we identify as a seat without headrest-there will be no headrest holes. If your seat comes with a factory headrest then this may be purchased as an extra. Apologize as no armrest cover is available.