I couldn't tell you. They came out when I was looking for something a little hot but not harsh. Folks were saying you get that with 59/09's so I picked up a set. The treble pick up in a Custom 24 is super hot (HFS = Hot Fat Screams), and so I was looking to get something a little milder than that. Well the 59/09 is and it isn't. In the Cu24 stoptail, it hits the prestage of the amp really hard. I get breakup really early, but it doesn't get shrill or brittle. I ended up likening this set more because it will go into break up really early. It's pretty cool.Alnico II?