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 red. Please use Panasonic BR435/2B or BR425/2B batteries. When night fishing, electric floats often drift out to sea for various reasons, or the lights on the electric floats fail due to poor contact, causing them to break. I myself experienced this a lot, and each time I had to buy electric floats for around 1000 yen or float tops for around 500 yen at the fishing tackle store. (/ _ ; ) I really hated that cycle, 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 them once. Thank you very much m(_ _)m Also, since these are handmade, please refrain from purchasing if you have any reservations.