METCO 2003-2004 Cobra - Auxillary Idler Kit 90mm This popular kit is designed to bolt on with no modifications and virtually eliminate belt slippage at the supercharger pulley. The included aluminum mounting bracket is precision-machined and mounts to existing bolt locations, and the unique design provides unmatched durability and strength. This kit includes a black hardcoat-anodized 90mm idler pulley, which is the smaller size that serves to maximize belt wrap in applications using stock size supercharger pulleys.