| Business | Phone |
| Shell Engineering Inc 430 Cribbage Ln # A, San Marcos 92078 | (760) 471-6670 |
| Progressive Molding Inc 170 Bosstick Blvd # 101, San Marcos 92069 | (760) 940-8161 |
| Plasmetex Industries Inc 1425 Linda Vista Dr, San Marcos 92078 | (760) 744-8300 |
| Nytronics 920 Rancheros Dr # B, San Marcos 92069 | (760) 743-6113 |