The WORK S45E-9188 features our high latest compressor cover design that supports more airflow and higher efficiency over our smaller S4E counterpart. The 91mm compressor wheel is 5 axis machined from billet aluminum and features a clean sheet of paper design that compliments the 96/88mm turbine wheel perfectly. Each unit is assembled using our premium hydro-dynamic bearing structure featuring our proven 360° billet thrust group for durability. 3 stage balancing ensures a quiet, long life and the gloss black bearing housing coating will keep your turbo looking great for years to come. This unit is right at home on a single turbo build looking to make efficient power without higher boost pressures or a twin turbo big block build needing a fast spooling 3000 HP capable pair of turbochargers. Call us today with any questions, we will be happy to help!