An acoustic wave device includes a substrate and a plurality of piezoelectric thin film resonators formed over the substrate. A boundary between the first gate insulating film and the second gate insulating film is composed of a straight portion parallel to a side of the pattern of the body diffusion layer and a corner portion surrounding an vertex of the pattern of the body diffusion layer from a distance. The first and second housing parts are connectable in a manner enabling them to be axially moved relative to each other in the connected state by an extent defined by at least one stop on the second housing part that is engageable with at least one opposing stop on the first housing part. The gear externally fitted and fixed to the throttle shaft has, on a fixing ring that is externally fitted to the throttle shaft, a housing groove for housing the pin, the housing groove being impelled against the pin by a spring. A spring extends from a center portion of a rear wall to bias the stack of material toward the front wall and to impart a curvature in the stack of flexible material. In certain embodiments, the cement compositions comprise carbon fibers, rubber particles, a hydraulic cement material, sufficient water to form a pumpable slurry, and optionally other ingredients including a dispersant, a weighting agent, a retarding or accelerating agent, or the like.