Positive Grid Spark 40 With Bag - UsedSpark is a 40 Watt combo with bass, mid and treble tone stack controls, plus mod, delay and reverb effects, tone starter preset programs, a built in tuner, tap tempo and more. The Spark amp and app work together to learn your style and feel, and then generate authentic bass and drums to accompany you. The Positive Grid amp comes with the original carrying case, USB cable and power supply.