US Patent 9885571 Attachable level with rotatable bubble vial

A level is selectively coupled to a work piece and includes a housing, an adjustable clamping mechanism configured to selectively couple the housing to the work piece, a first bubble vial coupled to the housing and operable to indicate a first levelness of the work piece, and a second bubble vial rotatably coupled to the housing about a first axis. The second bubble vial is operable to indicate a second levelness of the work piece.