Roland BT-1.

Versatile Add-on Trigger Pad for V-pads and Acoustic Drums.

The compact and affordable BT-1 Bar Trigger Pad makes it easy to add electronic triggering to any drum kit. With a curved shape that mounts on the side of a V-Drums V-Pad or acoustic drum, it provides convenient playing access without disturbing your existing kit layout.

The BT-1 is great not only for playing sounds in a V-Drums module or SPD-series percussion pad, but also for convenient control of a variety of functions like start/stop of backing songs and phrase loops, and much more.