Self powered guitar combos

 

— the presence of an autonomous power supply in the combo amplifier.

This feature allows you to use the device regardless of the outlets — for example, for outdoor performances. The source of autonomous power is most often replaceable batteries, for example, 6 AA cells; however, a built-in battery may also be provided. The first option is convenient because dead batteries can be quickly replaced with fresh ones, the second one is that the battery is initially supplied in the kit, and when it is discharged, it is enough to charge it, there is no need to spend money on buying new batteries.

Note that most self-powered models are relatively compact and low-power devices — powerful acoustics would require too expensive and bulky power supplies.