Race Tech Shock Spring Yamaha Yz450F / Yz450Fx Race Tech revolutionizes handling with their comprehensive selection of Hi-Performance Springs, designed for optimal front and rear balance. Boasting over 900 designs, their springs are crafted using the finest materials for unbeaten quality. Features: Extremely accurate rates The tightest tolerances in the industry Heat-treated and Shot-peened Preset to eliminate sacking-out Extremely lightweight Made in the USA