An accumulated use time for cargo handling vehicles is accurately displayed by a time measuring device even if the time measuring device fails and is replaced. These techniques and apparatuses enable an audio-production device having a flexible transducer conformed to a person’s pinna to create audio within the person’s external ear canal. The sensor may include a set of electrical leads that enable the sensing area to communicate with the processing and communication zone and with external devices, and a guard ring surrounding the first conductive surface and the second conductive surface to minimize an effect of stray capacitance. The body slides in the hydraulic line in response to pressure changes in the hydraulic line, and occupies hydraulic line volume, to stiffen the hydraulic system and reduce system sluggishness. The outer sleeve on the supporting core is non-displaceably mounted on at least one bearing and that the outer sleeve is mounted on at least one displacing point at a distance from the bearing so as to be displaceable perpendicular to the longitudinal axis of the supporting core in order for the curvature of the outer sleeve to be adjustable. A III\u2013V compound semiconductor having Bi added thereto is used for a base layer of a GaAs-based or InP-based HBT.