Another major concern on hyperbaric oxygen chambers is the stitching. Some stitching is triple stitched and others are only single stitched. Be aware that some are triple stitched just near the zipper and single everywhere else.
Please don't be fooled by seeing triple stitching when its just near the zipper and only 1 ply everywhere else, kinda misleading!
If the chamber is going to be used for many years after the warranty period it is probably better to make sure that all the stitching is triple ply for durability, especially if the chamber is going to be folded frequently and moved from place to place. If not being unfolded and folded often, then a lower ply count can be fine.
Some are threaded with nylon and others can be polyester threaded. The stitching that stretches the least will fray the least. Eventually all treading will fray, even if 20 to 30 years later.
Warning: make sure that your stitching is not seared, (seared stitching). This is usually on the knock off chambers that are made so cheaply that parts are seared. "Running problems" are the reason that companies sear their threads. The better quality stitched chambers do not have seared stitching, period. I would look over the chamber all over to make sure the threads aren't seared if buying a used one or renting that you don't want them to come back and say you mishandled it. Just check for sears.
Seared stitching is good but not for chambers that are under pressure. Over time the problems can happen, not usually when someone first buys it. Most people don't even know to even look for for seared stitching.
Anti static stitching: The stitching can with the chamber create static on some. I do not like the hyperbaric oxygen chambers that I shock me when I get out of it. You touch a door knob and you get zapped. Totally not cool. It mostly happens if the hyperbaric chamber is used on a carpet. Not so much with wooden floors.
Tensile res8stance: this has to do with material stretch. Some threads have a higher tensile strength than others. Some double up or triple ply their stitching to give more resistance but if the wrong material can cause static electricity with some homes.
By getting the right threading it can mean getting a cheap chamber or a very expensive chamber. The more expensive hyperbaric chambers have a better record of avoiding "running" of its threading.
Warning: Know before you buy if your seams are or are not heat sealed. Splitting of the seams is the worst thing that can happen to the stitching, very common after a few years on cheaper models, and they are usually the ones that do not have the extended warranty options. That should be a good sign that they are not made well from the start.
Please take my hyperbaric quiz and let me know if you have concerns about stitching. If you are going to be traveling with your hyperbaric oxygen chamber, this is the most important factor if upgrading to better stitching.