| Business | Phone |
| Fusion Systems 520 Executive Dr, Willowbrook 60527 | (630) 323-4115 |
| Frank Novotny & Assoc Inc 825 Midway Dr, Willowbrook 60527 | (630) 887-8640 |
| Frank Professional Elec Engrs Willowbrook 60527 | (630) 325-5220 |
| Espo Engineering 855 Midway Dr, Willowbrook 60527 | (630) 789-2525 |