The Tektronix 067-0102-00 is a battery-operated ("pocket") time mark generator that produces 10 µs or 1 ms pulses at 0.1% accuracy.

Tektronix 067-0102-00
Pocket Time Mark Generator
Tektronix Time Mark Generaror 067-0102-00

Produced from 1966 to (?)

(All manuals in PDF format unless noted otherwise)

It is powered by a 9 V battery and uses a 100 kHz and a 101 kHz crystal.