The Air F National Seat Spring (part number 901970) is a quality replacement air f national seat spring for the operator cab system on Capacity yard trucks and terminal tractors. Sourced to meet or exceed Capacity OEM specifications, this part delivers dependable performance in the demanding conditions of warehouse, distribution center, and port operations. Weight: 2 lbs. Dimensions: 12" × 6" × 5". Yard Truck Specialists has been supplying genuine terminal tractor parts since 1986 — every order ships fast from our Pennsylvania warehouses with expert support available.