| 摘要 |
A detachable vial insert (11) for a spirit level (10) is disclosed comprising a casing defining a cavity for receiving a pair of semi-transparent liquid-filled vials (16) having a longitudinal curvature containing a bubble (30) for providing an indication of a true level plane when the bubble (30) is positioned between two markings (30) placed on the body of the vial (16). The vial insert may be used as a pre-calibrated stand-alone device or as a replaceable insert for a spirit level (10). |
