Dual coil pickup
A pickup up with two coils most commonly referred to as a humbucker primarily because they make up the vast majority of such pickups. The advantage of a humbucker compared to single coil is that the two coils can be designed to cancel (or almost cancel) the Hum produced by a single coil system. Examples of dual coil systems are for example the P-pickup. The J bass also operates as a humbucker when both coils are used. In some cases coils can be switched on - and off to create a brighter sound of a single coil, or switch to a darker and Hum-free humbucker sound.