| Business | Phone |
| Detection & Measurement Systs 10101 Southwest Fwy 400, Houston 77074 | (713) 541-9800 |
| General Monitors Inc 9776 Whithorn Dr, Houston 77095 | (281) 855-6000 |
| Global Detection 1233 Confederate Rd, Houston 77055 | (713) 984-1437 |
| Isc 1201 Bering Dr, Houston 77057 | (713) 784-6986 |