If interested, Amazon is running a sale ($5.00 off) for an imperial thickness gauge for the Domino 500.
https://www.amazon.com/Imperial-Thi...=UTF8&qid=1492396333&sr=8-15&keywords=festool+domino
https://www.amazon.com/Imperial-Thi...=UTF8&qid=1492396333&sr=8-15&keywords=festool+domino