EMG is the standard when it comes to active pickups. EMG has many different models but they are mostly known for their metal pickups. The EMG 81 and 85 are their most popular pickup models. These are what you will find in 90 percent of guitars that come with EMG pickups. The EMG KH21 Loaded Pickguard set is a way to completely change the tone of your strat or strat style guitar. With this setup you get a fully wired setup of dual EMG 81 pickups with dual volume controls and a master tone. All you have to do is wire it to your output jack. The 81 is a well known pickup and has been a staple in metal music for about 20 years. It has a pretty unique tone if you compare it to passive pickups. The 81 first came out in 1981 along with the EMG 85. The 81 is the more focused pickup of the two. It has a searing high gain metal sound. When I play music with a lot of palm muting I can get an awesome tone. The 81 really shines when you are playing tight chugging riffs. Tight chugging riffs and single note lines are what this pickup is best at. When you downtune all these traits just help to keep the sound nice and tight. It is very hard to get a muddy sound from this pickup. With the built in preamp it has a ton of output. Because of the built in preamp the magnets dont have to be as strong so there is less string pull so you get more sustain. Because the pickup is so focused on metal it may for some people be lacking in other areas. I dont know anyone who likes the 81 in the neck position. ESP makes a few guitars that come with it in the neck position and I think most people swap them out. More popular neck position EMG models are the 85 and the 60. The 85 is similar to the 81 but has a fatter tone so it works well with high gain lead tones. With the 60 you get a pickup that is setup for the neck position only. The 60 is good for clean tones and nothing else pretty much. It does not have the output of the 81 or 85 so it cant really drive an amp but this also gives it a clean tone similar to that of a passive pickup. EMG's are known for their sterile clean tones so having a 60 gives you a pickup built just for that. If you have a strat and one to make it a metal machine in one easy setup this is probably the simplest way.