I purchased an Omega Patriot 75 cu. ft. 4500 psi air tank with standard valve from AOA. Had it filled and noticed that the gauge did not register as I filled my air rifle. Called AOA up and explained what was happening. The tech gave some instructions on how to check the gauge for debris and then to call them back. Still did not work, so I called AOA back and a new gauge was mailed. Got it within two days! Works perfect! Also, I mentioned that I must have thrown the QC test plug away by mistake and a replacement was sent at no charge! Awesome service AOA!