| Business | Phone |
| International Consultants Inc 225 S Troy St 120, Royal Oak 48067 | (248) 336-8456 |
| Kolar Corp 412 S Washington Ave 200, Royal Oak 48067 | (248) 543-0500 |
| Zenith Design Inc 612 E 4th St, Royal Oak 48067 | (248) 542-1080 |
| Tmc Group Inc 306 S Washington Ave # 230, Royal Oak 48067 | (248) 545-4359 |
| Techno Research 4940 Delemere Ave, Royal Oak 48073 | (248) 658-1800 |
| Climatek Engineering Inc 4262 Edgeland Ave, Royal Oak 48073 | (248) 554-9840 |
| Datong Designs Inc 415 S West St 300, Royal Oak 48067 | (248) 548-8181 |
| Design Analysis Inc 811 N Main St, Royal Oak 48067 | (248) 541-0535 |
| Ets Engineering Inc 406 S Washington Ave, Royal Oak 48067 | (248) 744-0360 |
| Mc Donough Engineering 225 E Hudson Ave, Royal Oak 48067 | (248) 544-3500 |
| Ceg Assoc 104 W 4th St, Royal Oak 48067 | (248) 542-0700 |