S&S Diesel Gen 2.1 CP4 Disaster Prevention Kit (CP4-6.7F-BP-G2.1). Reroutes the CP4.2 pump's case fuel through a return filter, so metal from a failing pump doesn't reach the injectors. Fits the 2011-2019 Ford F-250/F-350/F-450 pickup and F-350/F-450/F-550 cab and chassis 6.7L Power Stroke. Add-on for our remanufactured 6.7L Power Stroke long block; ships loose in the crate with your engine.