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 numbers 1000, 5000, 6000 and 6500 identify the suspension base. A 6000/517 and 6500/517 are all the same seat. Please note your seat may come with no headrest and this we identify as a bucket standard without factory headrest.(There will be no headrest holes). If your seat comes with a factory headrest then you have the option to cover this. Please note we do not have the PRO version.