AC to AC converter question

[Stephen]

There are three Heavy Duty sockets on this Converter. 1500W Max. I intend to step down 220 volts AC for my 110 volts AC equipment. I am puzzled with the red socket marked as FIXED 100VAC. Instructions does not explain. What does it mean or what is it's use? Thanks.

[kirkfranks]

Stephen,
Is there any way to post a larger photo. The thumbnail does not get bigger so we cannot read it.

[Stephen]

Thanks . Sorry I am unable to upload a larger scanned attachment.
Here is what is written on the Card Box
Box Conventional Transformer
Single Function (Either step-up or step-down)
Continuous Use Design
With Enamel Paint Coating (serves as Insulation)

NEWSTAR AC to AC Converter
Features :
Input Voltage : AC 220V 50/60Hz or AC 110 50/60Hz
Output Voltage: AC 110v 50/60Hz or AC 220 50/60Hz
Output AC socket : Three Universal Sockets (one socket
with Fixed 100VAC
Socket with 3 wires (one is safety ground wire)
On/Off rocker switch with indicator lamp
Insulated base platform for safety insulation
Automatic thermal fuse
Glass fuse
Metal casing with superior air ventilation design
Overheat protection
Overload protection

Stephen