Brother P-Touch 580C User Manual page 13

This is a lightweight and portable machine. It can be used anywhere by installing
six (6) AA alkaline batteries. When you change the batteries, always replace all
six at the same time.
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Be sure to insert the new batteries within five minutes of removing the
old ones, otherwise the message in the working area and any messages
stored in the memory will be lost (unless the machine is plugged into an
AC outlet with the AC adaptor).
If alkaline batteries are not used, large fonts and bar codes cannot be
printed.
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