We found these while researching options for our Adventure Motorcycle Luggage list. What makes the Amphibious Moto Bag so different is a proprietary air valve that makes it easy to compress the bags. Capable of expanding from 20 liters to a staggering 50 liters per bag these are the largest dry bag saddlebags you can buy.
The Moto Bag is made from polyvinyl chloride (PVC) using welded seams for a completely waterproof bag. The top of the bag is closed with full length velcro. Once the velcro is closed you roll the top of the bag down as tight as you need it and each end has a plastic clip to hold it in place. There are two additional straps that compress the top of the bag even further. There are two wide velcro straps per side to allow you to compress the diameter of the bag and keep them as close to the bike when mounted as possible.
Mounting the bag is straightforward but not perfect. They are designed to mount to any rack, on any bike, in any location you can make them fit. That also means they never fit any of them perfectly. The back of each bag has 8 rings for the strap that come with them. You can loop the strap through a ring and then clip it to the other side of the bag. While versatile the adjustment is difficult to tighten and the bags always hang loosely. I preferred using the four velcro side straps to loop around the side racks and then tighten the entire bag to the rack. The bags still sagged but the straps kept them from moving around and compressed the contents evenly. It also kept the back of the bags from being pushed into the exhaust.
These things are massive. Making multi-day trips are a cinch to pack for. I overpacked for a two-day weekend for two people and still had more than enough room to carry more. Taking a weeks worth of clothes, food, shoes, toiletries, and whatever else you can think of is easy. Because the bags sag when mounted the weight stays low. On the plus side they stay high enough that they are never in danger of dragging during spirited cornering, even two up.
We ran into sun, rain, bugs, and ocean spray on my test trip. The bags handled all of it superbly. Nothing inside ever got wet. The best compliment I can give them is I never thought of them once they were mounted. A lot of that can be attributed to them being less wide than the handlebars even when fully loaded. One gripe with hard luggage can be the width of the mounted setup. Despite 100 liters of total available capacity these stay nice and tight to the bike and are never what will hit obstacles first.
Final thoughts: I am not 100% sold on these bags. The mounting system could be greatly improved. Wolfman Luggage has a much better compression strap mounting system that is also universal. On the other hand these are huge! They worked perfectly and other than the mounting system are a really well designed bag that have proven durable so far. Priced at $347 they are pretty good bargain as well.