The Brian Crower Valve Spring and Retainer Kit is designed for high rpm use. Brian Crower valve springs are wound from only the highest grade, super clean, chrome silicone alloys and feature proprietary processing procedures for consistent pressures.Brian Crower titanium retainers are CNC machined from 6AL4V round bar titanium to exacting tolerances.Spring Pressure:BC1600 Seat: 1.420″ @ 80 lbs / Open: 1.000″ @ 178 lbs / Coil Bind: 0.850″ (No machine work required)Note:– Titanium Retainers included in this kit.Fitment:2004-2021 Subaru STI & Type-RA – EJ2572002-2014 Subaru WRX – EJ2552004-2013 Subaru Forester XT – EJ2552005-2009 Subaru Legacy GT & Spec B. – EJ2552005-2009 Subaru Outback XT – EJ255EJ-Series Turbo Engines – EJ205 / EJ207 / EJ22T / EJ255 / EJ257 / EJ257B