Need an ignition interlock device near Sheboygan? Intoxalock is available at RPM Speed and Custom, a certified Intoxalock ignition interlock installer. We can install your breathalyzer in cars, trucks, vans and other vehicles.Founded in 1979, RPM Speed and Custom is a small auto parts & supplies store in Sheboygan, WI. As an authorized TonneauCovers.com dealer, RPM Speed and Custom is committed to helping you make the best TonneauCover decision for your truck and lifestyle. RPM Speed has been an ignition interlock installer for Intoxalock for over 10 years.