- Each grade has distinguishing features as well as a different signature (in grade order: Appleton Tracy & Co., Waltham Watch Co., P.S. Bartlett, Wm. Ellery, and Home Watch Co.).
- As Royal Robbins introduced new grades he upgraded the grades.
- For example, the WWC grade is close to AT&Co grade except it has fake jewel setting. The AT&Co grade was upgraded with the regulator and index located on the balance bridge like the 3/4 plates. Also, the serial number was moved from the barrel bridge as on other grades to the plate.
- The PSB grade was given an expansion balance whereas the Ellery had a steel balance or a fake (closed) expansion balance.
|
