CONCORD, N.H. (AP) – It has taken four years, but the state has selected two companies to supply ignition locks that prevent repeat drunken drivers from starting their cars if they’ve been drinking.

The Executive Council on Wednesday approved contracts with two companies to install, monitor and maintain the breath-alcohol ignition locks for the next five years. The devices act like a car key. The driver blows into a tube and the car won’t start if his or her breath shows a blood-alcohol level above a certain point.

The state passed a law in 2002 requiring the devices for some convicted drunken drivers, but they couldn’t be installed until companies were hired to provide and service them.

Offenders pay for the installation, monthly monitoring and resetting if a driver’s car ignition is locked repeatedly due to high blood-alcohol levels. The device will remain in the car or cars regularly used by the offender for no less than six months and no longer than two years.

The Executive Council’s decision to approve contracts with two different firms means offenders will have a choice when the court mandates they install an interlock device.

Consumer Safety Technology Inc., of Iowa, charges $75 for the initial installation. Draeger Safety Diagnostics of Colorado charges $60. David Arringdale of Consumer Safety Technology said an exact date hasn’t been set for installing and servicing the devices; he estimated it would be in early fall.