Guardian Ignition Interlock is MA’s most affordable ignition interlock device. Guardian’s device is discreet and one of the easiest to use devices on the market. With over 30 years of experience, Guardian is one of the most trusted iid brands. Our location at 253 Quincy Street is MA certified with expert technicians for all your interlock installation and calibration needs. Guardian alcohol monitoring products include 24/7 customer support so we're always here when you need.