Ideal for lowered SoftailsStronger than stock springs prevent bottoming outBig Red springs are recommended for solo riders rated for 1200 psiBig Blue springs are recommended if occasionally carrying a passenger or the rider weight is 220-290 lb. rated for 1300 psiBig Gray springs are for lowered machines that often carry passengers or for the rider whose weight is 300+ lb. rated for 1400 psiFit OEM and Progressive Suspension shock absorbersMade in the U.S.AEU: Big Red springs are recommended for solo riders rated for 8,27 MPaEU: Big Blue springs are recommended if occasionally carrying a passenger or the rider weight is 99,79 - 131,54 kg rated for 8,96 MPaEU: Big Gray springs are for lowered machines that often carry passengers or for the rider whose weight is 136,08 kg+. rated for 9,65 MPa