CIRCLE XRAY fittings are marked with a black X inside of a black circle. These modified closures are secured during conditions XRAY, YOKE, and ZEBRA. However, personnel may open these fittings without special authorization when proceeding to battle stations or as required in routine inspection checks. You may open these closures, but you must secure them immediately after use. You will find this classification on the following closures:

l Doors to magazines and handling rooms

l Hatches that do not have a scuttle and lead to magazines and handling rooms

l Access to the missile handling and checkout area compartments

l Scuttles in hatches to the shaft alley, pump rooms, magazines, and handling rooms

l Access to the gas and fuel station and filter rooms

l Access to the oxygen-nitrogen ^rooms (compressor and producing)

l Access to the switch gear room, ammunition hoist, and elevators

l Access to the underwater log room

l Access to the equipment rooms that are unoccupied

l Scuttles for passing ammunition

YOKE fittings are marked with a black Y. These closures are secured during conditions YOKE and ZEBRA. You must have proper authorization to open fittings with this classification when the ship is at condition YOKE or

ZEBRA. You will find this classification on the following closures:

Hatches that are provided with a scuttle and lead to shaft alleys and pump rooms

Alternate accesses to machinery rooms

Weather deck hatches not classified as XRAY

Some alternate accesses on the DC deck and above

Access to the ^{windlass room}

Access to the generator rooms

^{Access to the} air compressor room

Access to the air-conditioning machinery room

Access to the refrigeration machinery room

Access to the elevator machinery room

Access to the missile director machinery room

Access to the drying room

CIRCLE YOKE fittings are marked with a black Y inside of a black circle. These modified fittings are secured during conditions YOKE and ZEBRA. However, these fittings may also be opened without special authorization when personnel are proceeding to battle stations or as required in routine inspection checks. Again, you must secure these closures immediately after use. You will find this classification on the following closures:

. Hatches that do not have a scuttle and lead to the shaft alley and pump room

. Scuttles in the deck to the shaft alley and pump room

l Doors at the bottom of the trunk to the shaft alley and pump room

l Access to the steering gear power and ram room

l Access to the chill room

ZEBRA fittings are marked with a red

^{z. These closures} are secured during condition ZEBRA. You must have proper authorization to open fittings with this classification when the ship is at condition ZEBRA. You will find this classification on the following closures:

All remaining doors and hatches for routine access

Access to all shops, labs, commissary, utility, control, and hospital spaces

Access to all offices

Access to equipment rooms occupied when associated control room is in use

Main access to machinery spaces

Access to issue rooms

Access to the steering gear room

Access to the enclosed operating stations

Access to hangar and flight deck control stations

Access to the garbage disposal room

Access to the trash burner and bin room

CIRCLE ZEBRA fittings are marked with a red Z inside a red circle. These modified fittings are secured during condition ZEBRA. CIRCLE ZEBRA fittings may be opened with the commanding officer's permission during prolonged periods of general quarters. The opening of these fittings allows evolutions such as the preparation and distribution of battle rations, opening of limited sanitary facilities, ventilation of battle stations, and access for aviation personnel to the flight deck. When open, CIRCLE ZEBRA fittings must be guarded so they may be closed immediately if necessary. You will find this classification on the following closures:

. Limited doors or scuttles from the weather deck to the crew's galley

. Doors from aviators and flight crew ready rooms to the flight deck

DOG ZEBRA fittings are marked with a red Z inside a black D. These modified fittings are secured during condition ZEBRA and darken ship conditions. You must have proper authorization to open fittings with this classification when the ship is at either condition ZEBRA or darken ship. You will find this classification on the following closures: l Doors to the weather deck, excluding those classified XRAY or YOKE, that do not have a darken ship switch or a darken ship curtain l Airports (portholes)

WILLIAM fittings are marked with a black W. These fittings are kept open during all material conditions. WILLIAM fittings are secured only as necessary to control damage or CBR contamination and to make repairs to the equipment served. You will find this classification on the following fittings: 

l Vital sea suction valves that supply the main and auxiliary condensers, fire pumps, and spaces that are manned during conditions XRAY, YOKE, and ZEBRA

. Vital valves that if secured would impair the mobility and fire protection of the ship