FIG. 1 is a top perspective view of an I-beam spirit level; FIG. 2 is a front elevation view thereof; FIG. 3 is a left side elevation view thereof; FIG. 4 is a top plan view thereof; FIG. 5 is a bottom plan view thereof; FIG. 6 is a rear elevation view thereof; and, FIG. 7 is a right side elevation view thereof.