Abstract: The present invention is directed to environmentally friendly levels. Through the use of renewable resource or environmentally friendly liquids in the transparent tubes of a level, it is possible to provide a level that will not harm the environment if the liquid escapes from the tubes as well as reduce the use of petroleum based fluids. In one embodiment, the level contains non-petroleum based hydrocarbons and a water-based solution of dissolved ionic solids. In other embodiments, the level contains non-petroleum based hydrocarbons and water-based solutions of dissolved ionic solids with increased boiling points and lowered freezing points. In other embodiments the level contains arced tubes, standard tubes and combinations of both wherein the liquid in the tubes may be the same or different.

Abstract: The present invention is directed to environmentally friendly levels. Through the use of renewable resource or environmentally friendly liquids in the transparent tubes of a level, it is possible to provide a level that will not harm the environment if the liquid escapes from the tubes as well as reduce the use of petroleum based fluids. In one embodiment, the level contains non-petroleum based hydrocarbons and a water-based solution of dissolved ionic solids. In other embodiments, the level contains non-petroleum based hydrocarbons and water-based solutions of dissolved ionic solids with increased boiling points and lowered freezing points. In other embodiments the level contains arced tubes, standard tubes and combinations of both wherein the liquid in the tubes may be the same or different.

Abstract: A slope level for measuring the slope of a surface is provided. The slope level includes a body having a front face and a back face and defining a first planar measurement surface. A transparent arced tube is disposed in an opening in the body. An aperture in at least one side of the level frame can allow for viewing of an arced tube through a clear cover protecting the tube. The clear cover may comprise a plastic material positioned between the side of the frame and filler material inside the frame and defining the groove, with the portion of the clear cover at the aperture extending outward so that the clear cover is flush with the side of the frame.