Long and narrow flotation bags fit on either side of a kayak's center support pillar. This item is for ONE STERN BAG. The Infinity Series Bags are 10-gauge Urethane material that won't leak or delaminate. Stern dimensions inflated: 33.5"L x 10"D x 13"W, 3"W at tip. There are many, many kayak models. You will need to measure the space in your kayak that you want to fill in order to determine which flotation bag will work for you. Choose bags that size or larger.