I built these into a baritone guitar I designed and made on recommendation from the guys at the Seymour Duncan factory themselves.
I just had to make a few design changes to accommodate the battery.
I wired the guitar in 1 vol, 1 tone, 3 way switch format. The pickups themselves connect with push on connectors making it very easy to change them out if desired.
Sound.
Beware these pickups are extremely powerful and will overload the input stage of a solid state input stage (modelling amplifiers for instance) quite easily. It is best if you turn on a little compression first of all. On valve amplifiers there is no such problem and you will be rewarded with a superb crystalline clarity on low guitar volume settings all the way to a superb overdriving of the input stage when the volume control is full.
You can achieve the same with a solid state amplifier but as stated with compression on.
There is absolutely no noise at all from these pickups, no buzzing that you get with non active pickups (stage lights are good to induce this), no hiss from the circuitry and when you take your hands off the strings no mains induced buzz.
Battery life. I left the guitar lead plugged in to see how long the battery would last. Up to now I have had the same battery for around 100 hours continuous use and it still works. Only time will tell how long it will last before being replaced.
All in all these guitar pickups work great with low B strings all the way up to the top of the register. The balance between the pickups is superb as long as you get the pickup height right. The neck pickup is very mellow sounding, the bridge pickup as you would expect is sharp but still with a lot of depth. When you blend both pickups together you get another very distinct sound. It is quite a honky mellowness.
The pickups come as a matched set marked B and N with all the cables, 4 potentiometers, 2 capacitors, nuts, washers, screws and springs. All you need to supply is the pickup rings, switch and jack socket. Of course if you are putting them into and existing guitar you will have all of that already. You must use the 25K pots that come in the kit though as the design calls for them. Also you must use the supplied capacitors too.
I can thoroughly and heartily recommend these.