| Business | Phone |
| Jeffigan Engineering Inc Hayward 94541 | (510) 537-1707 |
| Kenneth M Jones Design Hayward 94541 | (510) 889-8370 |
| Lea & Sung Engineering Inc 2495 Industrial Pkwy W, Hayward 94545 | (510) 887-4086 |
| Mac Rae Technologies Inc Hayward 94541 | (510) 886-2366 |