This unique pen has a small green LED tucked into its tip right next to a high quality medium ball point. Twist the switch on the top of the pen and you will be able to see what you are entering into the log without having to light up the whole cabin. Comes with a clear cap to help prevent leaving it on by accident, and also allows you to clip it to your chart or pocket if you just need a small light to see by. Lasts for hours on 2 LR44 1.5 volt batteries located in the top.  SW .3 lbs.