Pressure suit

Pressure suits appear different depending on where they are made but they always have an airsuit and pressure helmet.

Airsuit. A suit of armor is needed to utilize this leather and alchemically-tailored slip, but once integrated it hermetically seals the wearer from the outside. While wearing a suit of armor equipped with an airsuit, you have advantage on saving throws made against pressure. A fine or masterwork airsuit does not require integration into a suit of armor to be worn.

Pressure Helmet. This glass, leather and metal contraption fits over the head with a clear plate in front of the face. While wearing a pressure helmet, you gain advantage on saving throws against gasses and vapors. A pressure helmet cannot be disarmed. In addition, you can connect the pressure helmet to a specialized fine or masterwork air safe (see Aquestio), providing enough air for up to 1 hour of breathing for a Medium-sized creature (or 2 hours of breathing for a Small-sized creature).