Gear set for X-10 gear drive, also compatible with ProCharger and Alston gear drives. Please consult us at sales@mtpturbo.com to determine ratio/part number of gear set desired. Some additional information may be found here: https://mtpturbo.com/qcgd/X10gearcharts.pdf and here: https://mtpturbo.com/qcgd/X10R106gearcharts.pdf