This is GNP's Lightweight Alternator pulley. It's T-6061 aluminium, CAD designed, CNC milled, then it's hard anodized in three rich colours to add a little bling to go with the lightened performance benefits.
This is a stock size alternator pulley, just a lot lighter, so your stock belts will work.

The stock alternator pulley is 195 grams
The GNP Lightweight alternator pulley is 71 grams
That's a 124 gram difference, that's .27 of a pound reduction.

Try it on it's own or with our Lightweight Crank Pulley and/or our Lightweight Water pump pulley.

Fits:
-2013-2021BRZ
-2013-2016 FRS
-2017-2021 Toyota86