This refers to a monoplace hyperbaric chamber (designed for a single person) capable of reaching 2.0 atmospheres absolute (ATA) pressure. The "44D" likely denotes the chamber’s diameter (44 inches) or model number. These chambers are commonly used for mild hyperbaric oxygen therapy (mHBOT) at lower pressures (1.3 to 2.0 ATA) and are popular for athletic recovery, wellness, and certain... https://recover.ae/products/44d-2-ata-hyperbaric-chamber-walk-in-oxygen-therapy