| 968 / | HD | HOROLOGY |
| 748 | DD | MEASURING, COUNTING, CALIBRATING, TESTING, OR REGULATING APPARATUS (measuring devices and calibers in general G01B; counters in general H03K) [G04D 7/00] {11} |
| 769 | DD | .~ Timing devices for clocks or watches for comparing the rate of the oscillating member with a standard (supporting devices for clocks with built-in recording apparatus subclass 681; measuring short time intervals subclass 844; frequency measuring in general H04B, G01R) [G04D 7/12] {2} |
| 770 | DD | .~.~ Only for measuring [G04D 7/12B] {2} |
| 774 | | .~.~.~ For the control mechanism only found from outside the clockwork [G04D 7/12B3] {2} |
| 775 | DD | .~.~.~.~> For measuring amplitude [G04D 7/12B3B] |
| 776 | DD | .~.~.~.~> For measuring frequency [G04D 7/12B3C] |