They make replacement LED/batteries for night bobbers. Tape one of these to the middle bottom of your favorite champ/Z disc with multiple layers of scotch and you're in business. If you must use an opaque disc, tape it on the top with duct, because of the way the disc flexes when it lands it will snap scotch on top. I tape it down with two strips over the LED, perpindicular to the LED, then one strip on both sides holding down the initial strips tightly, parallel to LED, and finally one strip on both sides holding down the second strips tightly, perpindicular to LED but not over it, just outside and flat on the disc. If you do this, hit all the trees you want and that LED's going nowhere. You can get these at any Wally World or Meijer. They do advertise them for dg too but it's the same thing. They are reusable and say they last twenty hours. Don't waste your time on the green ones, get in bed with red and make sure to get the "pop" in and out type and not the "swivel" to turn on and off type. Cost around $3.