The mini-hb's that BK did are for the LP deluxe and were mini mules. They can be fitted into a Firebird mount (I have one and it is in a mounting ring). They sound a little warmer and fatter than the regular deluxe, and they have the BK open sound when you turn down the volume. Comparing them to an original Firebird (63) pickup, they are actually very similar, but when you compare them to a newer firebird, the BK wins hands down. The new firebird has a much more bland and distorted tone.