And when the EMP washes over your home/office it will most likely be off and most likely survive. If you are doing your monthly finances at the time and it is on, it will be destroyed. The slide rule rules!!! I keep a pocket Pickett for fun...the window has a small crack, and it is missing a very tiny screw (1 of 8). I brought it to my engineering company one day and showed the 20-30-something group how it worked. I then did a full page of calcs they did in Excel, and even with the limits of visual resolution came within an acceptable percentage of their calc.