OxyHelp metal body soft chambers are popular for home use, the advantage is price and storage space. However, most other soft chambers reach a pressure limited at 1.3 ATA.
OxyHelp medical can go to 2 ATA (3 times the pressure) which covers most of the HBOT protocols and non-medical to 1.5 ATA which has also a big range of HBOT applications. 1.3 ATA is mostly used effectively for neurological issues (brain responds better to lower pressure), all other medical conditions require higher pressure.
Zipper can be damaged sometimes if not being handed carefully. With long time use, the window or zipper will break making the urethane chamber useless. Once the window comes off or zipper teeth weaken, they cannot be repaired without professional help. Especially dangerous when small children are around. They can poke the chamber with something sharp and render it unusable.