Thank you for viewing my product m(_ _)m Not only the BR435/2B lithium battery size, but also the shorter BR425/2B size can be used. The light color of this product is rainbow. Multiple lights flash and emit light. Please use Panasonic BR435/2B or BR425/2B batteries. When night fishing, for various reasons, my electric float would drift out to sea, or the electric float would malfunction due to poor contact, and the light would not turn on. This happened to me very often, and every time I had to buy a new electric float for around 1000 yen or a float top for around 500 yen at the fishing tackle store. (/ _ ; ) I got tired of repeating this, and to help those who have had the same experience and feel the same way, I decided to make them by hand. I would be happy if you would try it once. Thank you very much m(_ _)m Also, since these are handmade, please refrain from purchasing if you have any reservations.