- Adams Magnetic Products Co
- Akron Porcelain & Plastics Co
- Cercom Inc
- Cling-Cal Corp
- Cling-Cal Corp
- Coors Tek
- Coors Tek
- Curran-Pfeiff Corp
- Isolantite Manufacturing Co
- Keramos Inc
- Lapp Insulator Co LLC
- Maryland Lava Co
- Newell Porcelain Co
- Porcelain Products Co LTD
- Rockwell Automation
- Star Porcelain Co
- U S Technical Ceramics
- Victor Insulators Inc