| Business | Phone |
| Draeger Interlocks 5936 South Loop E, Houston 77033 | (713) 738-9733 |
| Guardian Interlock 5611 Dashwood Dr, Houston 77081 | (713) 349-9096 |
| Ignition Interlock South 5936 South Loop E, Houston 77033 | (713) 738-4846 |
| Interlock Systems Of Texas Inc 9811 North Fwy B210, Houston 77037 | (281) 448-1934 |