| Business | Phone |
| Willco Construction Co Guardhs 6011 Executive Blvd, Rockville 20852 | (301) 231-9456 |
| Us Security Inc 1100 Taft St, Rockville 20850 | (301) 309-8292 |
| Proactive Special Security 15200 Shady Grove Rd # 350, Rockville 20850 | (301) 515-0212 |
| Inter Con Security Inc 2101 E Jefferson St, Rockville 20852 | (301) 231-8084 |