Abstract: A level is provided, including a main body, at least one bubble vial and an arm. The main body includes at least one reference surface, a first clamping surface, and at least one aperture formed through the main body. The bubble vial is attached to the main body for indicating the orientation of the at least one reference surface. The arm projects through and slidable within the at least one aperture of the main body and includes a second clamping surface. An adjustable clamping distance is measured between the first clamping surface of the main body and the second clamping surface of the arm. The arm is slidable within the at least one aperture for adjusting the adjustable clamping distance.