Plastigage strings are a simple and accurate way to verify crankshaft, main and rod bearing clearances. Kit includes two green.001" to.003" and one red.002" to.006" (12" long strings) individually packaged inside calibrated sleeves. Detailed instructions are included. The key to success in a car building project is access to high quality, reasonably priced parts that get the job done right. Each All-star part is the result of our dedication to research and development. Once a need is established, parts are designed and manufactured by talented craftsmen, many of whom are racers and hot rodders themselves. Many All-star Performance parts are one-of-a-kind; you won't find them anywhere else.