A method for managing multiple hardware test module versions, software components, and tester operating system versions in a modular test system is disclosed. G1 is an aliphatic; cycloaliphatic, aromatic, arylaliphatic or arylcycloaliphatic spacer and E is a functional group. The tag detects shipping information, including temperature, humidity, shock, etc. An advantage of this invention is that the pressure profile of the hydraulic fluid is controllable and hence the integrity of the airframe is maintained. This indentation is used for collecting splashing water and removing the splashing water by way of the air guiding duct or a space between the friction ring and the shielding metal plate to the outside.