So far they only come out with the K-13. They are water activated and last for 400 hours of lighted life.They have a small bulb it the tail end that works rather well. I do think they will work better if trolled. I got four of them at the Iss. G.I. Joe's. They run out of stock fast so grab them while you can. I see it will be like last year on the K=13 no one could get there hands on at first.