ABY Line Selector Pedal

ABY signal switch pedal

Signal path from Y to A (red light), from Y to B (green light), or from Y to both A and B (yellow light)

Or, signal path from A (red light) to Y, or from B (green light) to Y, or from both A and B (yellow light) to Y

True bypass

http://www.tomsline.com/products_detail/productId=53.html