Very good and durable, and the tools are perfectly protected. I have a pickup truck with an open bed, which is why I got it. No problem with the rain!!

Compared to the DS 150, it has much less storage space. Additionally, the DS 150 has a drawer right below its lid. Other than that, the DS 165 is very nice, weighing the same as the DS 150 when empty. It has a tight closure and its lid stays upright. It also has slots to insert rails for nuts. Its handles are larger than those of the DS 150. I used it for about half a year, but it didn't suit me at all. The included compartments also didn't suit me. I went back to my old one (DS 150 1-70-321). Another thing that seemed dangerous to me is that the system for stacking the suitcase on top of another is indeed faster with springs, but these yellow pieces protrude, making them targets for sharp objects or corners, while in the DS 150 they are completely made of plastic, although they do collect dust. Of course, it loses in terms of speed. Finally, the price is steep. Personally, I was not satisfied at all.

Sturdy, to an excessive degree, like a plastic safe box(...). Excellent durability, which however has as an inevitable "side effect" the increased volume and weight (even when empty, you can feel the weight and if you put several things inside, it becomes very heavy), while the available internal space is limited by the thickness of the walls and the reinforcing "ribs".
The internal compartments are not of the same good quality as the rest of the toolbox. Their closure is very "fake".
The internal dimensions are shown in the photos.
It is worth getting it to put expensive electric/rechargeable tools inside, to keep them protected.