The Festool Carvex Circle Cutter Set Imperial works with all Festool Carvex jigsaw models to cut circles from 4-3/8" to nearly 10 feet (9' 10-1/8" ) in diameter. The set consists of the optional Guide Rail Base Adapter and Circle Cutter for the Carvex jigsaw. The Base attaches tool-free to to the jigsaw and, when not being used for circle cutting, it can be used to adapt your Carvex jigsaw to a Festool guide rail to get extremely straight cuts in either direction. The Circle Cutter rolls up for compact storage when not in use. For best results, Festool recommends use of a scroll type blade, such as the S 75/4 K or S 50/1.4 FSG (#'s 486563 or 486564) when making circle cuts. Made in Germany.