-Gauge Build-in Battery RS232 USB 5VDC Powered Digital Display Pressure Gauge Manometer G1/8 0-30atm(0-450psi) Brass<br />-Widely used in petroleum， chemical， metallurgy， food and other industries including gas， liquid<br />-Range : 0~30atm / 0~450psi<br />-Panel outline size : 40mm<br />-Outplut mode : RS232<br />-Units : psi， atm<br />-Working Temperature : -20→ to +85→<br />-Thread : G1/8(can be customized)<br />-Power : Build-in 3VDC Battery / 5VDC USB <br />-Dimension : 48 x 40 x 40 mm<br /><br />Operation instruction :<br />Press ON to open the unit， Long press ON for 5 seconds to close the unit， or the unit will auto turn off when there is no pressure<br />psi/atm - unit convert button， at 0.0atm condition， long press this key for 5 seconds， the display will be &quot;000&quot;.<br /><br />Package included:<br />1 x Digital Pressure Gauge