Is the category for mandatory action signs which provide mandatory notices and instructions.
To signify hatches on a lifeboat, or fully enclosed rescue boat, must be closed
To signify that an earth terminal must be connected
To signify that the mains plug must be disconnected from electrical outlet for the purposes of maintenance of electrical equipment, in the case of malfunction or when left unattended
To signify a mandatory action
To signify the lifeboat is to be lowered or the location of the control to lower lifeboat to the water
To signify a liferaft must be lowered or the location of the control to lower liferaft to the water