From the manufacturer:
Ultra high output humbucker built for aggressive playing styles. Recommended for punk, garage, thrash, metal and other heavy rock styles.
Designed for the heaviest tones a passive pickup can produce. The combination of three ceramic magnets, over-wound coils and twelve black oxide cap screws make the Invader an electrifying force of energy. The wide magnetic field pumps power into your amp with a totally heavy sound. Comes with four-conductor hookup cable.
Available for both neck and bridge positions - most commonly used in the bridge position. The Invader neck pickup has considerably reduced output for tonal versatility.
For all instruments. The wide pole pieces work for both humbucker and Trembucker string spacing.
Synyster Gates / Avenged Sevenfold, Troy VanLeeuwen / Queens of the Stone Age (bridge), Mike Chlasciak / Halford (bridge), Whitey Kirst / Iggy Pop (bridge), Joey Roxx / Burn Halo, Rick Jackett / finger eleven (bridge), Will Adler & Mark Morton / Lamb of God (bridge)
Magnet type: 3 large ceramic bars, D.C. Resistance 7.2k-neck, 16.8k-bridge"
There is a separate SD model, the Synyster Gates Invader SH-8SG and TB-8SG, which is identical to this model, except for the color options of the pickup screws (chrome, white, and gold vs. black)
Best videos/sound clips:
Here we have an official SD video (the player's name was unlisted, unfortunately) playing Pillars of Creation by Keith Merrow. This shows off the pickups heavier tones and shows how it sits in the mix:
Here we have the positively epic 2014 Seymour Duncan 12-way bridge metal pickup shootout in all its glory! The top video is the "rapid fire" comparison (2 min total), and the bottom video is the 15 minute in-depth comparison. I've included these videos here as the SH-8 is in the video (bottom row 2nd from the right). What's great is that you get to hear the same song being played on the same guitar by the same player. The licks are tasteful and it's mic'd well. Now as a critique, the mix is pretty heavy and with the bass and kick drum I find it hard to tell much about the quantity/quality of the bass output of these pickups. My take on this video though: All of these pickups do a good job – really you could play metal with any of these and be happy. Note: As this is an older video it is missing the Black Winter, Pegasus, and Nazgul bridge humbuckers.
The player is Keith Merrow and the song is "Pillars of Creation". Keith is playing a Strictly 7 Guitars "Cobra" Baritone 6-string 27.5" scale guitar through a Rhodes Colossus H-100 head.