A combined square leveling for combing multiple construction tools into a single device includes a framer's square for measuring angles during construction. A tape measure is retractably positioned within the framer's square and the tape measure is urgeable outwardly from the framer's square for measuring distance. The tape measure is biased to retract into the framer's square. A bubble level is coupled to the framer's square to determine if a surface is level. A laser level is slidably coupled to the framer's square to emit a beam of light to establish a reference point on a distal object.

A combined square leveling for combing multiple construction tools into a single device includes a framer's square for measuring angles during construction. A tape measure is retractably positioned within the framer's square and the tape measure is urgeable outwardly from the framer's square for measuring distance. The tape measure is biased to retract into the framer's square. A bubble level is coupled to the framer's square to determine if a surface is level. A laser level is slidably coupled to the framer's square to emit a beam of light to establish a reference point on a distal object.

A combined square leveling for combing multiple construction tools into a single device includes a framer's square for measuring angles during construction. A tape measure is retractably positioned within the framer's square and the tape measure is urgeable outwardly from the framer's square for measuring distance. The tape measure is biased to retract into the framer's square. A bubble level is coupled to the framer's square to determine if a surface is level. A laser level is slidably coupled to the framer's square to emit a beam of light to establish a reference point on a distal object.

A method of calibrating a levelling offset meter (LOM) for calculating the angular offset between a plane parallel to the LOM and a predetermined reference plane, the LOM comprises a bull's eye spirit level having a bubble and a processor coupled to an image, comprising: capturing, by the imager, a plurality of images of the spirit level associated with a respective plurality of known angular offsets; calculating in respect of each image a pixel distance from the bubble center to a predetermined zero offset pixel, thereby obtaining a plurality of pixel distances, each pixel distance associated with a known angular offset; fitting a function to a plurality of pairs of values, each pair of values comprising a pixel distance and its associated known angular offset; and storing the function in a memory.

Embodiments provide a calibration tool for measuring a distance between a transducer and a liquid surface of an open channel, including: a pole; a flat board attached to the pole, configured to reflect a signal from the transducer, wherein the flat board is substantially perpendicular to the pole; a level device provided on the flat board, configured to ensure that the flat board is substantially parallel to a bottom of the open channel during a measurement; and a measuring scale provided on the pole.

Embodiments provide a calibration tool for measuring a distance between a transducer and a liquid surface of an open channel, including: a pole; a flat board attached to the pole, configured to reflect a signal from the transducer, wherein the flat board is substantially perpendicular to the pole; a level device provided on the flat board, configured to ensure that the flat board is substantially parallel to a bottom of the open channel during a measurement; and a measuring scale provided on the pole.

A combination of a cover plate and a drain, preferably a floor drain is described. The cover plate is provided with first locking means and the drain is provided with cooperating second locking means for releasable connection of the cover plate to the floor drain. The cover plate is a temporary cover plate for use during installation of the drain. The cover plate may be used for a temporary protection of a drain during installation of the drain and for installing and adjusting the inclination of the drain without the need of separate levelling tools. To obtain this the cover plate is provided with levelling means for determining the orientation of the cover plate and thereby also the drain in relation to a horizontal or a vertical plane. The first locking means or the second locking means comprises a weakening arranged such that at least a part of the locking means is preferably damaged when the cover plate is removed from the drain to ensure that the cover is not reused.

A level includes a frame having a top planar surface, a bottom planar surface, and a web coupling the top planar surface to the bottom planar surface. The top planar surface and the bottom planar surface are parallel. The level further includes a vial supported by the frame. The vial has a longitudinal axis passing through a center of the vial and a body defining an interior containing a liquid and an indicator bubble. The level further includes a plurality of LEDs. Each of the LEDs has a light emitting point, and each of the plurality of LEDs is positioned adjacent an end of the vial and is oriented such that the light emitting point is positioned within the interior of the body of the vial.

A level includes a frame having a top planar surface, a bottom planar surface, and a web coupling the top planar surface to the bottom planar surface. The top planar surface and the bottom planar surface are parallel. The level further includes a vial supported by the frame. The vial has a longitudinal axis passing through a center of the vial and a body defining an interior containing a liquid and an indicator bubble. The level further includes a plurality of LEDs. Each of the LEDs has a light emitting point, and each of the plurality of LEDs is positioned adjacent an end of the vial and is oriented such that the light emitting point is positioned within the interior of the body of the vial.

A level includes a frame having a top planar surface, a bottom planar surface, and a web coupling the top planar surface to the bottom planar surface. The top planar surface and the bottom planar surface are parallel. The level further includes a vial supported by the frame. The vial has a longitudinal axis passing through a center of the vial and a body defining an interior containing a liquid and an indicator bubble. The level further includes a plurality of LEDs. Each of the LEDs has a light emitting point, and each of the plurality of LEDs is positioned adjacent an end of the vial and is oriented such that the light emitting point is positioned within the interior of the body of the vial.