Ben,Couldn't agree more, Boonjin is doing amazing things and need a decent pen, i'll be testing out the new release in the classroom tomorrow, the school i'm at has just currently ordered 100 Vishay TSAL6400 LEDs and plan on putting together a heap of pens with the gifted and talented students.I have one question, you use a rechargeable AAA, and as far as i'm aware, you were using the above diode which has a forward voltage of 2.6 and a AAA only has 1.5V. how much does it affect pen performance or have you changed diodes?