This is a 2jzge/2jzgte UR pulley set.  The set consists of 1) Water pump pulley 2) Alternator pulley 3) Power Stearing pump pulley 4) Idler pulley.  These are stock diameter pulleys.  UR developed this version because the performance benefits of weight reduction outweigh the need for underdrive, especially for audio enthusiasts as some audio competitions require voltage to remain at a specific level. Stock diameter is also important for factory or aftermarket superchargers. Superchargers need the stock diameter to keep the same boost you had with the factory crank pulley. The big weight loss gets you a lot more power to the wheels.

UR = The first power pulleys for American, Asian & European sport compacts.
UR = The lightest pulleys for the biggest HP gains and the most gas savings.
UR = The leader in HP increase per dollar.
UR = CAD designed & CNC machined in the U.S.
UR = The best balance, no wobbling, hopping and they fit right the first time.
UR = The finest finish, ready for anodizing or plating of any kind.
UR = The most comprehensive warranty (5 years) for peace of mind.
UR = The widest range of applications.
UR = The best technical and customer service.
UR = 14+ years of "real world" use from street to strip to rally to road course.