RTS OE / Rostra Precision Controls, Inc. is the Original Equipment manufacturer of vacuum modulators. Rostra Modulators are the highest quality in the industry. Complete and universal, problem solving designs, function perfectly the first time, every time. Yellow stripe, with one single hose connection for High Vac lower altitude driving. Usually found on larger engines with strong vacuum signals, and trucks with earlier governor shift point calibration. Usually found on 72-81 Fully adjustable for the right shift & feel adjustable 7.5-10 pounds