Stock diameter (2.85 inches) Paxton pulley that has been coated with Carbinite grade 1 coating. This coating reduces belt slip. $80 shipped lower 48 states. More info on this coating can be found here: Automotive Performance
The pulley was coated in 2012 but with my over size crank pulley it was putting me a little past the 55k max impeller speed so I switched to a 3 inch coated pulley. The coating probably doesn't even have 300 miles on it.