| Business | Phone |
| Neomek Inc 411 Rockwell Ct, Willowbrook 60527 | (630) 789-4800 |
| Prototech Engineering Inc 411 Rockwell Ct, Willowbrook 60527 | (630) 920-0597 |
| Raths Raths & Johnson Inc 835 Midway Dr, Willowbrook 60527 | (630) 325-6160 |
| Ricardo Inc 7850 S Grant St, Willowbrook 60527 | (630) 789-0003 |
| Vibration Institute 6262 Kingery Hwy 212, Willowbrook 60527 | (630) 654-2254 |
| Whiting Technologies Corp 646 Executive Dr, Willowbrook 60527 | (630) 850-9680 |
| Integrated Project Management 200 S Frontage Rd 220, Willowbrook 60527 | (630) 789-8600 |
| Ketchmark & Assoc 100 Tower Dr 240, Willowbrook 60527 | (630) 850-7774 |