How we make money

Some interlock companies may pay us when someone books an install through a link on this site. When a link is paid, the page says so.

Payment doesn't change the facts we publish, the order of any table, or which companies appear. Tables are sorted by the data shown in them, such as the number of state approvals or service centers, and every company on a state's approved list is shown for that state whether it pays us or not.

We don't sell your information. The ZIP code search on state pages runs in your browser and isn't sent to us.