Heavy duty 6-foot flexible fiberglass folding mason"s ruler, built to withstand extreme weather conditions. Graduations are engraved into the fiberglass, giving them a much longer life than traditional wooden rulers. Rhino Rulers resist weather and scratching, and are actually washable. Finally a folding ruler that lasts.Will not warp or peel in wet weatherWashable - dirt, mud, concrete, etcLifespan is 3 times that of wooden rulersBack side of ruler is used for laying bricks in conjuction with concrete blocks as backingExcellent for any outdoor / wet use