It can be really handy to know when you get a bite on a line, especially if you have a set up with more than one rod. These little rod tip sensors are designed for sea fishing and they attach to the tip of the rod. Once on the rod, they will automatically turn on. They will be visible for up to 100m away. They cleverly detect a bite but will not detect rod and line movements from wind etc. They come with two attachment clips either 3mm or 5mm so they should fit on most rods. There are three in the set and they have a long-life battery.