The Thermo brand valves have a little sticker on them (below the outlet) with a "service pressure" value. However, that value can be misleading because nothing prevents someone from installing a mismatched valve in a cylinder. A trained fill station operator following best practice will be guided by the markings on the crown of the cylinder not the label on the valve. Those permanently stamped markings on the cylinder itself determine the maximum fill pressure of the cylinder, not the service pressure label on the valve. Likewise, the markings on the nut of the pressure relief device (PRD) installed in modern valves indicates release pressure of the PRD and not service pressure of the cylinder.