Although the Frodo drybag does come in a larger size (3.6 cubic feet), we only stock the "Medium", which is 2.2 cubic feet and runs $169. It is the volume that will fit into the back of most inflatable kayaks, and it will tie down easily into any AIRE brand model (other than the Force) since those kayaks come with lots of tie down loops.
The drysuit zippers used on the Frodo are more convenient than having to roll down a four-strap standard bag, but if you use these around salt water it is mandatory that you hose the zippers off after use. Well, unless you want to purchase a new one every two years....
The 2.2 cubic foot Frodo is roughly 16" wide, 26" long, and about 10" tall. AIRE gives somewhat larger dimensions for some reason, but this is what we've measured. The zipper runs full length and a bit down the sides. In other words it opens plenty wide to get all your gear in. The Frodo's have carry handles of course, and four tie down points on the bottom.
The Extra large size Frodo bag can be special ordered, but not via the shopping cart - you will need to call. This larger size is more of a substitute for a standard 3.8 foot bag like the River Pack. It runs $199 and is orange & grey instead of blue & grey. All are constructed of PVC fabric and close with a TiZip™ waterproof zipper.