Electric Fence Light w/ Z Bulb Plus Designed to work with 10-mile fence chargers and larger. The larger the fence charger, the brighter the light becomes. It lights up with every pulse of the fence charger and can be seen up to one mile away. 360 degrees and from the air as well. Can be mounted on top of a wooden post or on T-post using our special T-post Bracket (item #EFLAE) which is sold separately . Uses very little voltage off of fence when Knocker spark gap is adjusted correctly. Great for remote locations and easy to install. Know in a flash that your fence is working properly just by looking out a window. The Knocker body also gives off a knocking sound that lets you know that all is OK when you cannot see the light. The larger the fence charger, the brighter the Z-Bulb model becomes. Made in Cookeville, TN, USA This product requires a Spark Gap Adjustment before working properly. Click here to see instructions (with full color pictures).