This is one of the neatest products I’ve come across in a awhile… these LED Dog Collars are available right now on eBay for ONLY $1.58 + FREE Shipping! They are waterproof and come in a variety of sizes and colors: white, red, blue, yellow, green, pink, orange and multi-color. There are 3 lighting modes to set: constant on, strobe and flashing.
NOTE: Batteries are not included with purchase. You’ll need to buy 2 CR2032 Cell Buttons. I found a 5-pack of these batteries on eBay for only $0.77 + FREE Shipping!