These pump transfer blades are an aftermarket direct replacement for Stanadyne 20511, commonly used in Roosamaster / Stanadyne DBG JDB DB2 DB4 Fuel Injection Pumps. Product carries a one year, unlimited mileage warranty. Not sure what parts you need? We offer free troubleshooting and technical support for all common agricultural diesel applications. We also offer Refurbished services for these applications, Call us today at 800.961.9290 for more information.