Professional Systems Technology
- Fire Protection - 922160
- All Other Specialty Trade Contractors - 238990
- Security Systems Services - 561621
- Facilities Support Services - 561210
- Communication Equipment Repair and Maintenance - 811213
- Audio and Video Equipment Manufacturing - 334310
- Testing Laboratories - 541380
- Engineering Services - 541330
- Electrical Apparatus and Equipment, Wiring Supplies, and Related Equipment Merchant Wholesalers - 423610
- Electrical Contractors & Other Wiring Installation Contractors - 238210