Up for sale is TEAM 2016-2018 600 Pro-RMK 155" Polaris PRIMARY SPRING POL. The vendor part number is 210135-011. Please read the title to know what is for sale Venom primary springs are made from high tensile silicon wire to maintain rate over many cycles. Primary springs control engagement and shift RPM. Fine tune your primary clutch with Venom springs manufactured from high tensile wire to exacting tolerances.