A brake adjustment indicator for an air brake having a brake chamber, comprises a body including a cavity within, the body including a passageway having an inlet and an outlet communicating with the cavity, the inlet and outlet being adapted for connecting to an air line connected to the brake chamber...http://www.google.de/patents/US5474154?utm_source=gb-gplus-sharePatent US5474154 - Air brakes adjustment indicator for vehicles such as trucks and the like
