I stumbled across this product via a video ad. https://www.tractorsupply.com/tsc/product/efl-electric-fence-light-efl-light101-1294347?cm_mmc=feed-_-GoogleShopping-_-Product-_-1294347&gclid=CjwKCAjw0vTtBRBREiwA3URt7hzmM8dVE-YSqxgnQVkbrKT2-LOtVvOScIDEkaTfLTICTdZ1b6qHMRoChnQQAvD_BwE
... in case the url doesn't work here, just search "Tractor Supply Company Electric Fence Light"... I wanted to see if I could do a cheap (free) diy and found your post in my search results. I'm no electrician, so I don't want to experiment at using old Christmas light bulbs without some input. Has anyone tried direct wiring Christmas tree light bulbs to an electric fence?