| Business | Phone |
| Control Works Inc 11805 Pika Dr, Waldorf 20602 | (301) 870-8900 |
| Greens Mechanical Svc 3454 Gough Dr, Waldorf 20602 | (301) 645-0234 |
| Mclean Controls Inc 21 Industrial Park Dr # D, Waldorf 20602 | (301) 843-3292 |
| Mechanical Design System 1535 Pin Oak Dr, Waldorf 20601 | (301) 885-3210 |