I have a Paraframe (or is it a PFII, it's the bigger one). The thumb stud has always bugged me because it would scrath the back of my hand when I reach into my pocket. The knife id clipped to my pocket. My knife went through the dryer recently. My wife found it with the blade partially extended, stuck into the lint trap filter. Now the thumb stud is gone. It's a bit more difficult to open one handed now.