| Business | Phone |
| Calchina Engineering Inc 1898 S Carlos Ave, Ontario 91761 | (909) 947-6688 |
| Cortek Engineering Inc 1522 E Francis St, Ontario 91761 | (909) 930-1788 |
| Hi Q Engineering 1441 S Balboa Ave, Ontario 91761 | (909) 947-9916 |
| Biomedical Engineering Svc Tch 4025 E Guasti Rd, Ontario 91761 | (909) 605-6555 |