The DiMazio X2N humbucker is a seriously edgy bit of kit. Designed from the ground up to pound and abuse your poor tube amp with insanely high output to squeeze every last drop of awesome tone from your valves. To the uninitiated that might sound like a bad thing but those in the know know that driving those valves until they scream for mercy is the secret of the most desirable distortion tones (overdrive pedals are for wuss bags). So if you want the same tones as the metal gods then you'd do well to get an X2N humbucker in your guitar by any means necessary!
Black pickup covers because lets face it, black is the colour of metal.
Here's what Dimarzio say about the X2N humbucker
The X2N is a “take-no-prisoners, in-your-face” humbucker. Twin, wide-bar pole pieces give the X2N a nasty, dangerous look — and rightly so. Our highest gain pickup was created to push tube amps into total overdrive. Put one in the bridge position for a powerful jolt to the voltage the amp sees from your guitar. The result is a sound that can only be described as blistering. The magnetic field of the X2N is very powerful and focused. It captures the character of whichever guitar it’s in. If your guitar is warm sounding, the X2N will act like a sledgehammer. A bright-sounding guitar will go into total scream mode. And the X2N still has versatility: single-coil and series-parallel modes are particularly effective, because the X2N pickup’s power gives these sounds more authority than is possible with weaker humbuckers.