If you coil-tap via a .022 capacitor it becomes frequency selective. Top end of the frequency spectrum is single coil but lower end remains humbucking. Great for 'cool' or vintage type HB's where the single coil by itself can sound a bit thin and weedy. Works especially well in the bridge position. You can either fix-tap by a switch or you can make it completely variable by tapping via a spare tone pot. Another coil-tapping trick.... you can achieve a simple coil tap by just using your existing tone pot without having to change to a pull-pot or tap switch. Let me know if you're interested and I'll give you more details.