An objective lens is formed as an objective lens element with a diffractive surface on one side. More particularly, the endotracheal tube includes primary and secondary cuffs, in the form of inflatable balloons. The shank has at least one groove having an abutment portion, a seating area, and a tapered portion. , and the Shore D hardness is at least 35 and not more than 60. The pressure-sensitive adhesive sheet according to the invention can be cured even by exposure to ultraviolet rays at a low intensity or for short time so that it can contribute to energy saving and productivity improvement as a sheet for processing, fixation or surface protection of a semiconductor wafer.