The FG 40-30 is a compact roll-off safety device with electrical contact that has been specially developed to prevent an unbalanced door from rolling uncontrollably as a result of a mechanical defect. Once the roll-off protection has been activated, it cannot be reused and must be replaced. A red pin indicates the status of the roll protection. The electrical contact must be connected to an emergency stop of the relevant control to ensure that the drive stops immediately when the roll-off protection is activated.