The smaller pulley will deliver 9-11psi at sea-level on your Jeep Wrangler 4.0 3.8 or 3.6 equipped with a RIPP Supercharger system.
This pulley is designed for high elevation clients to correct the superchargers impeller speed to offset elevation boost loss. It can be driven safely from sea level to high elevation without tune issue. Current RIPP tunes are generally set for this pulley, you can ask firstname.lastname@example.org before you install and they can direct you in the right direction for tune updates.
Made from 6061 billet aluminum the unit is also deliver faster spool up. This unit can be used with stock internals but an intercooler is a must.
Also known as the Altitude pulley across the Jeep communities.
Depending on your set up running more boost will require a re-tune of your electronics...
Jeep Wrangler TJ and JK will require shorter belts