US Patent 7568292 Level

A level being one in which a mounting base 2 is configured so that a first unit 2A that presses against the inner surface of one side of the container case 3 and a second unit 2B that presses against the inner surface of the opposing opposite side of the container case 3 are slidably assembled by way of a slide mechanism S; the slide mechanism S is formed so that the assembly contact surfaces 5 and 6 of the first unit 2A and second unit 2B are formed as slope guide surfaces 5 and 6; the slope guide surfaces 5 and 6 make contact with each other, the second unit 2B is slidably configured in the slope direction in relation to the first unit 2A.