Some new tech for The Choking Tower… 5e’ified.
REBREATHER
Technological Gear, Rare
Weight 1 lb., Capacity 10, 1 charge per hour of use
4,500 gp
A filter mask or rebreather, is a clear plastic shield worn over the entire face. The mask has ionized filters and scrubbers that 
purify the air the user breathes in and give the mask an unintentionally fearsome look. While the mask has power, the wearer is completely immune to inhaled toxins or diseases. Even when the mask has no power, it grants the wearer advantage on all saving throws made to resist airborne toxins and diseases. It also grants advantage on intimidation checks when worn.