Breathing Air Cylinders Add to quote to select, and choose quantity on the quote form. Grid view List view 500 cu ft Exemption Special Permit Cylinder – 3/4″-14 NGT Inlet 500STEELAdd to cart Add to Quote 500 cu ft UN/ISO Cylinder – 25E Inlet 500STEEL-25EAdd to cart Add to Quote 585 cu ft Exemption Special Permit Cylinder – 3/4″-14 NGT Inlet 585STEELAdd to cart Add to Quote 585 cu ft UN/ISO Cylinder – 25E Inlet 585STEEL-25EAdd to cart Add to Quote