This LR Baggs Para DI unit is a great choice for acoustic guitarists. Note that it doesn't come with a battery.

Using this LR Baggs Para DI is easy. First, connect your acoustic guitar to the preamp. Then, connect the direct box to your amplifier or recording device. When using it, remember that it doesn't have a built - in battery, so you'll need to use an external power source. To keep it in good condition, avoid exposing it to extreme temperatures and moisture. Clean it gently with a soft cloth regularly.