Comparing USSR  РГ7 (RG7)  <a href="https://en.wikipedia.org/wiki/quartz_crystal" class="extiw" title="w:quartz crystal">W:quartz crystal</a> units used in <a href="https://en.wikipedia.org/wiki/crystal_oscillator" class="extiw" title="w:crystal oscillator">crystal oscillators</a>, with a modern one <i>(top right)</i>.
<a href="//commons.wikimedia.org/wiki/User:Dmitry_G" title="User:Dmitry G">Dmitry G</a>
<span class="int-own-work" lang="en">Own work</span>