EV² FUEL LEVEL- SW CURVE (240-33 OHMS) E-F - R43900 ISSPRO has been associated with instrumentation for heavy duty diesels since 1949. Our new PERFORMAX line was created especially for the diesel performance customer. ISSPRO'S PERFORMAX system includes: Stepper motor gauges with LED lighting - Heavy duty Electronic Signal Processor (ESP) - New high accuracy ISSPRO sensors