Abstract: A spirit level which includes an elongated frame with one or more vial receiving openings therein. A liquid-containing spirit level vial extends at least partially across each of the openings. A transparent sight plate is removably extended at least partially across each of the openings. Structure is provided for limiting the movement of the respective sight plate in the respective opening toward the spirit level vial located therein, and a gasket is positioned in the opening over the sight plate to retain the sight plate against movement away from the spirit level vial. The gasket is removably retained in its described position, and can be removed to permit the sight glass to be extricated to permit access to be easily had to the respective spirit level vial.

Abstract: A spirit level which includes a frame having a hole therein. At least one liquid-containing leveling vial is located in the hole and is preferably mounted in a vial holder having a central opening therethrough. The vial and, where used, the vial holder are fixed to the frame. Extending substantially across the hole is a transparent sight plate held in place by a resilient annular gasket. The gasket includes an angular, annular lip which is sealingly deflected against the sight plate, and a similar lip is sealingly deflected against the portion of the frame forming the hole. The gasket preferably includes a radially outward flange which maintains the gasket in contact with the transparent plate, and which extends into a radial groove around the frame opening.