When you just need a little extra weight, you want the Straight Line Sumo Seatsac 125 Ballast Bag. Put it where you want it, it''s designed to fit anywhere without hogging all the room in your boat. They''re easy to fill, too! Use any one of three standard 1" NPT valves, and adjust the bag with ease with the centered handle on top. And don''t worry that you''ll damage the bag by stuffing it under a seat the Straight Line Sumo Seatsac has internally glued and taped seams, along with a layered, woven polyester core for ultimate flexibility and puncture resistance.