From the manufacturer:
One of the most popular EMG’s, the 81 is the one that started a revolution. Utilizing powerful ceramic magnets and close aperture coils, the tone was designed with detailed intensity, incredible amounts of high end cut, and fluid sustain. Traditionally used in the bridge position of your guitar, this humbucking pickup will make your leads slice right through even the densest mix. When used in both neck and bridge positions the sound can only be described as blistering. Other recommended pairings include the classic 81/85 setup and the versatile 81/60 combo. EMG's solderless installation makes swapping your guitar pickups easier than ever.
IN THE BOX: EMG'S EXCLUSIVE SOLDERLESS INSTALL SYSTEM; SPLIT SHAFT VOLUME/TONE CONTROL SET, OUTPUT JACK, BATTERY CLIP SET, SCREWS & SPRINGS.
Here is a quick shootout video comparing the DiMarzio Evolution bridge pickup to an EMG 81. Both pickups are being used in a high-gain metal context and each pickup has its own character that makes for a subtle variance in tone. Beginning with the DiMarzio, the Evo has the natural responsiveness you get from a passive pickup, allowing for great dynamic response -- especially in terms of pick attack. It has a slightly brighter tone and a little less gain on tap, yet it is still very thick and crunchy with amazing articulation. The EMG in comparison (listen at 0:20) is a tiny bit darker sounding with more of a warm and rounded tone. The active nature of the pickup lends to a smoother, more compressed sound with great sustain and saturation. The DiMarzio Evolution and the EMG 81 bridge pickups are both solid pickup choices for high-gain applications; it ultimately comes down to preference between an active and passive sound.
The player is Salvatore Melillo and he is using an Ibanez RG550 (Evo) and RG321 (EMG) through an Axe FX through the Marsha HBE amp model.