The Oxyhealth Quamvis 320 is my ultimate favorite chamber by Oxyhealth. It is the only one of theirs that has the buckles. It goes to 1.4 ATA unlike the rest of their soft shell chambers that go to 1.3 ATA. It is big like the Vitaeris 320 hyperbaric chamber in that it is 32 inches in diameter.
The Oxyhealth Quamvis 320 has a urethane bladder and can handle 1.4 ATA with no problem. Urethane is much better than PVC material that so many of these cheap low grade chambers are made of. PVC stretches and is the type of material that has to be repaired very often after so many uses. The urethane that is reinforced with nylon helps so that it makes the urethane much stronger and very little stretching.
The buckles on the Oxyhealth Quamvis 320 are the easiest to buckle in.
Note: This chamber is not rated for 1.5 ATA. So, getting a higher psi pump is not something that I would recommend.
I strongly recommend getting 2 cooler ports if getting this chamber. Higher pressure = more heat. The 1.4 ATA get a little more warmer than 1.3 ATA and 1.5 ATA is much hotter. This is why when at 1.5 ATA I never recommend more than 2 people in it because it can get really warm if there is no cooler. Getting 2 holes punched through any chamber to add an external cooler (after market) or even an electricity port so you can add electricity will void any warranty so this is something to be aware of.
For those that don't need to go to 1.5 ATA and want more than 1.3 ATA, this is the chamber that is in the middle. This chamber has buckles and is super strong. I recommend this chamber for high traffic clinics since it has the nylon jacket around it that protects it.