<p><span class="h-card" translate="no"><a href="https://mastodon.social/@whitequark" class="u-url mention">@<span>whitequark</span></a></span> <span class="h-card" translate="no"><a href="https://hachyderm.io/@cliffle" class="u-url mention">@<span>cliffle</span></a></span> are these the ones that are named for inside diameter, standardized by outside diameter, and then materials got better and pipe walls got thinner?</p>