Marker unit for accumulator has longer hose like rubber ring that is covered with small material thickness by accumulator, where ring has inner color which is different from outside

摘要

The unit has a longer hose like rubber ring (2) covered with small material thickness by an accumulator (1). The ring has an inner color which is different from outside. The ring is inverted if the accumulator is charged, so that the color indicating the condition `charged` is visible. The ring is inverted again if the accumulator is discharged, so that the color indicating the condition `discharged` is visible.