The BWB40T does not have a roll-top closure: it has a waterproof zipper running along three sides that opens the bag like a book. One pull and you can see everything inside, without emptying the bag to reach the bottom.

It offers the same seal as a dry bag, with an IPX7 rating, but without the ritual of unrolling and rerolling it at every stop. The pull tabs are easy to grip even with winter gloves.

The manufacturer declares an IPX7 rating for the main compartment. On the IP scale, the number seven indicates protection against temporary immersion: it covers hours of heavy rain, shallow wading, and accidental washing.

The fabric is composite TPU with a water-repellent finish, which prevents the material from absorbing water. A bag that becomes saturated gets heavier and takes days to dry; that does not happen here.

The problem with a dry bag is that it’s essentially a sack: everything ends up at the bottom, and to get one thing out, you have to pull out ten. Here, the 40-liter compartment is complemented by two side pockets, one top pocket, and two internal pockets in the lid, one small and one large.

The things you need often remain within reach without opening the main compartment. Note, however, that the two side pockets are not waterproof, as the manufacturer states.

Across the lid are adjustable elastic straps: they’re where you stow a rain jacket, sleeping bag, or sleeping pad—the long items that wouldn’t fit inside anyway and that you’ll want to take out first.

The top pocket, on the other hand, is waterproof and holds documents and maps: easy to reach without opening the main compartment, and kept dry.

The base has a thickened, non-slip layer. On a synthetic leather saddle or an aluminum luggage rack, a loaded bag tends to slide forward with every brake, leaving the straps to bear the load on their own.

Thanks to the base’s friction, the bag stays where you put it, the fastening is subjected to less strain, and at the end of the journey you won’t find it resting against your back.

The manufacturer states that it is compatible with both traditional straps and quick-release straps. You don't have to buy a dedicated system: if you already have straps you like, they will work.

The bag rests on the passenger seat, luggage rack, or on top of a top case. At 55 centimeters long, it covers the surface of an aluminum top case well.

The zippers have pull tabs that can be gripped even while wearing winter gloves, when your fingers can’t feel anything and a bare zipper becomes a problem.

On the side, there’s a transparent card holder where you can slip in a card with personal details or an emergency contact—if the bag comes loose or something happens, it’s the only information that matters. Reflective strips complete the package for night riding.

A sealed, closed bag remains full of air. The result is a balloon that bounces on top of the saddle and acts like a sail on the motorway. The valve lets you release the residual air after closing: the load compacts and the volume decreases.

The buckles are Duraflex, a US brand that is the standard for technical backpacks. This is usually the first component to fail, and here it isn't generic.

Forty liters in the main compartment, in a body measuring fifty-five centimeters long, thirty-three centimeters deep, and twenty-four centimeters high. The empty weight is one kilogram and four hundred seventy grams.

The fabric is seventy percent TPU and thirty percent nylon, with 840D six-tenths-of-a-millimeter internal mesh. Measurements are taken manually by the manufacturer and may vary within tolerances.