This is the XS Scuba Standard Fill Checker Scuba Tank Cylinder Fill Checker Features:Gauge (p/n GB01) Easy read 2.75 diameter gauge Dual dial - 0 to 5000 psi and 0 to 350 bar Stainless steel case 1.5% Accuracy throughout full range Twist Bleed Screw (p/n AC361) Stainless steel bleed screw Positive seal PDVF seat Easy replacement bleeder screw Attachment Attachment to K valves only Large comfortable handwhee Gauge Boot(p/n GP17) Included with fill checker Snug fitting, silicone compound for protection of gauge "