Kala AMP-TWD-5U Tweed Ukulele/UBass Combo Amplifier Weighing less than 5 pounds and powered by two 9v batteries (Best with Polaroid 9V Batteries) Delivers great tone through a single 5 speaker and features onboard Volume Tone to fine-tune Equipped with a built-in headphone jack that automatically bypasses the speaker for quiet practice sessions Aux input for jamming along with tracks on your favorite media device (phone, mp3 player, iPod, etc.) For classic looks, this Kala amp comes dressed in a vintage-style tweed covering