| Business | Phone |
| Porter Engineering & Dev Co 8499 Lackland Rd # A, Overland 63114 | (314) 423-6725 |
| Midwest Engineering Svc 11252 Midland Blvd # 111, Overland 63114 | (314) 426-7172 |
| Maxin Technologies Inc 1908 Innerbelt Business Ctr Dr, Overland 63114 | (314) 426-0880 |
| Enders Design & Mfg Co 2700 Woodson Rd, Overland 63114 | (314) 427-5005 |