# Bubble Level Vial has two outside lines.



## jrepp44 (Jan 6, 2010)

What are the outside lines for?


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## jproffer (Mar 12, 2005)

Best guess....hot weather and cold weather.

In the winter the fluid expands a little, leaving less bubble, so use the inside lines. Summer, use the outside lines.

Or do what I do and just eyeball it so that however much space is between bubble edge and line on one side is the same on the other side. :thumbsup:


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## woodworkbykirk (Sep 25, 2011)

a 2nd line doesnt really serve much purpose. the only thing i can think of is that it might benefit a plumber who requires a minimum slope of drainage pipes


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## Oso954 (Jun 23, 2012)

> the only thing i can think of is that it might benefit a plumber who requires a minimum slope of drainage pipes


That is the normal purpose of the second set of lines. They are called pitch lines. Some levels used to have 3 (or more?) sets of pitch lines.

But I would check a new level for accuracy of the pitch lines, before relying on it.

With that Chinese level, you don't know whether the pitch lines would be American standard or metric.


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