Bests & Worsts Reviews from Amazon

I purchase one of these in Feb 2018. It arrived very quickly. However the canister seemed very light , but understanding the lightness of oxygen I assumed that was the reason this canister felt empty. When I removed the protective cap on the nozzle and following the instructions and pressed the trigger and inhaled. But I did not have any sensation of anything being released from the small canister. Also did not notice an change in my (air/oxygen) intake. I now truly believe I received this canister Empty for what ever reason... This may just leak out in storage or all canisters at the factory do not get filled? I just won't purchase this item again.