Our PBA (Personal Breathing Apparatus) bottle holder is designed to be mounted to our 3-bottle aircraft oxygen service carts. It is designed to hold two portable breathing cylinders (one crew cylinder and one portable cylinder), allowing for easy recharging of these O2 cylinders directly from the O2 service cart. The PBA bottle holder features a mounting plate with pre-drilled holes, allowing for easy installation on the cart (installation instructions are included).