- Amano Cincinnati
- American Time Recorder Co
- Chronomix Corp
- Chrontrol Corp
- Cincinnati Time Of Northern Ca
- Data-Chron Inc
- Data-Chron Inc
- Eastern Technologies
- Fei-Zyfer Inc
- Fei-Zyfer Inc
- Fei-Zyfer Inc
- Hallock Co Inc
- Intermatic Inc
- Joseph Tauser & Assoc Inc
- L-Ron Corp
- L-Ron Corp
- L-Ron Corp
- Line Master Industries
- Portatree Timing Systems
- PTF Inc Precise Time
- Raceamerica Inc
- Recordtime
- Signal Systems Inc
- Speed Control Inc
- Telechron Inc
- Time Tech
- Zyfer