Use parentheses to enclose qualifying detail that is of secondary importance to the main discussion. Use parentheses sparingly within sentences; commas often do the job better. Parentheses can also be used to enclose one or more entire sentences that add relevant but not essential detail to the main discussion.
The laser-alignment system uses small-diameter (approximately 0.25 in.), optical-quality mirrors embedded in the reflectors.
To make the piano's tone expressive, Brown files the crowns
and shoulders (tops and sides) of each hammer to their proper
shape if they are worn, fluffs up the hammer felt and, if
necessary, brightens the tone by applying a lacquer solution
under the crowns of the hammers.
--James Boyk, "The Endangered Piano Technician," Scientific American
The comparison between our data and models shows that for
most of the Cascadia coast the locked zone is restricted to a
swath 50 to 100 kilometers across that runs underneath the
continental shelf. (It widens considerably only near the coast of
--Roy D. Hyndman, "Giant Earthquakes of the Pacific Northwest," Scientific American