Mychron AIM beacon/transmitter box for laptiming and for use with your computer.
Good to have a spare if you already have one too. They are often stolen, lost, misplaced, or batteries die, so good to have another ready to go.
Great condition. As a bonus, I am including 8 brand new AA batteries installed and the external power wires cord for if you want to use it with an external battery. This is a must have track side for use with your computer.