... USED AS THE COMPONENT OF THE REGULATOR PRESSURE GAUGEdiameter:2.5"(optional diameter:1.5",2.0",3.0")way of connection:radial ... (optional:axial)case:golden steel casewindow: snap on polycarbonate lensrange of pressure: 0 ... "(or as your optional, like 1/8",3/8",1/2",bsp,bspt,npt,mpt)optional unit: bar,psi,mpa,kpa ...