Here's what Lollar say about the Imperial bridge pickup:
The Imperial® Humbucker captures the airy top end, balanced mid-range, tight lows, and complex overtones of the classic original PAF pickups. We then improved on the design to give you a more balanced frequency response.
Its medium output is in the vintage range with a hotter wound bridge pickup compared with a typical vintage set. Our unbalanced coils produce a tight bottom end that complements the pickup's fullness and causes overtones to build after each note is played. Overall, it has a full bridge tone.
DC: Bridge 8.4K