The EDS system Jon chose for his flights was the EDS-A1 with the CF-480 (high-pressure) glass-wound cylinder. With the cylinder able to be charged to 515 liters @ 3000 psi and the EDS automatic (electronic-fuel-injection) like performance for the brain, this allowed the maximum amount of oxygen with the minimum amount of space, weight and worry, problems seen with all other systems I researched for this purpose.