They are soft bags, zipped around the top where they open, and constructed of a nylon sort of material, covering about a quarter inch thick insulation.
I find them perfectly adequate, but always make sure they go on top, when stacked in a vehicle with other gear. I have one hard case, but haven't used it for a while. These bags have shoulder straps so I can carry two accordions, and, very often, a string instrument like banjo, or mandolin, all on one shoulder, with maybe a guitar and amp in my hands. Awkward for a long hike, but cuts down trips from the truck into the venue.
If someone can tell me how to post pictures, I will try it. Or maybe Andy W, who knows how these things work, will post pics of his bag. How about it Andy?