Zetec lightweight aluminium under drive bottom pulley.
For use on Silver Top, Black Top and ST170 engines.
Improves engine acceleration.
Weighs 0.43 kg & 132mm in diameter.
Std item weighs 1.43 kg & 155mm in diameter.
Anodized in a grey finish.
Helps combat water cavitation in high reving engines.
If used the front plastic timming cover requiers trimming.
Also requires shorter belt