I received the Fire Nock S3 package for Fire nock to test out and they have been awesome. Only thing I don't like is they are not the flashing model. They are a little pricey to start out around 60 bucks, but you can replace the batteries in them and they are only around 10 to 15 bucks for 3 batteries depending on where you get them. The started kit comes with three practices nocks and three lighted nocks. Turn on every time I shoot and easy to turn off, just hold it over something solid and drop the arrow nock down and turns right off. I would recommend them.