More about BRZ/FR-s/86 GFB Lightweight Pulleys for BRZ/FR-s/86 feature-1Like all GFB lightweight pulleys, these begin life as a single 6061-T6 aluminium alloy billet, which is then precision CNC machined to exacting tolerances. We then anodize them black for a stealthy appearance and superior wear resistance. This kit is supplied with 3 pulleys, not just for looks - the combined saving of 2.2 kg is significantly more than what is achieved by replacing just the crank pulley alone. The weight doesnÕt tell the whole story either - even though the saving is a significant 77%, the actual rotating inertia reduction (inertia is what counts) is 83%. Like all GFB lightweight pulley kits, you can feel the improvements: Sharper throttle response Engine feels more willing to rev Stronger ÒurgeÓ