EFL Electric Fence Light Z-Bulb Plus Flashes with every pulse & bulb will not blow!!! Made in USA!!! Included knocker with Tungsten Electrodes makes an audible sound Can be seen up to 1 mile or more away, 360 degrees and from the air For 10-mile fence chargers or larger and uses minimum voltage See YouTube Video: https://youtu.be/U_iuXzuSPEs