Need an ignition interlock device near Marshalltown? Intoxalock is available at Clemons Chevrolet, a certified Intoxalock ignition interlock installer. We can install your breathalyzer in cars, trucks, vans and other vehicles.Clemons Chevrolet doesn't just sell great cars to both Marshalltown and Des Moines drivers, we offer superior Chevrolet repair services and parts. We are located in Marshalltown, IA and our family has proudly served the area since 1997. We have been installing ignition interlock devices for Intoxalock since 1990.