Fox Suspension Steel 3.25" Travel Rear Shock SpringComing equipped with a robust steel construction, this mountain bike (MTB) rear shock spring is durable and reliable as you dominate your way from trail to trail. All standard steel springs are black and are marked with their spring rate in lbs/in (in 50lb increments) and the total travel of the spring itself. Standard black springs should only be paired with shocks having less travel than the travel marked on the spring itself. Features: Material: Steel Use: MTB Type: Rear Shock Spring Spring Travel: 3.25" Compatibility: All Fox coil rear shocks Size: Multiple options available to selectManufacturer’s Part Numbers: 039-09-001 Black 350lb 1.390x6.689" 039-09-002 Black 400lb 1.3850x6.634" 039-09-003 Black 450lb 1.3850x6.760 039-09-004 Black 500lb 1.3850x6.300" 039-09-005 Black 550lb 1.3850x6.700" 039-09-006 Black 600lb 1.3850x6.880"Buy Fox Suspension Components from Chain Reaction Cycles, the World’s Largest Online Bike Store.