| Business | Phone |
| Gary Walker & Assoc Engineers 1836 Patricia Ave, Simi Valley 93065 | (805) 527-1139 |
| Jay Harland Precision Design 662 Weller Ct, Simi Valley 93065 | (805) 527-5685 |
| Korwin Advanced Technology Simi Valley 93065 | (805) 582-9767 |
| Ventura Design Svc 905 Quimisa Dr, Simi Valley 93065 | (805) 527-6875 |