The G620 Series back mount closed circuit sight gauges provide front viewing of the fluid level clearly delineated by a redline on white background integral to the sight glass all secured within an aluminum body (HIGH-LOW markings). A wetted dial thermometer provides an analog display of the fluid temperature. Standard Features: Centerline lengths from 3 to 12 inches Back mount .90 inch SQ body machined from extruded aluminum bar stock Fluid level visible from front of gauge (.50 inches wide) Viewing enhanced by redline on white background integral to sight glass 1.38 inch diameter dual scale dial thermometer, 50° to 300°F and 10° to 150°C Aluminum tube shields thermometer probe extending into reservoir HIGH-LOW markings on aluminum body 1/2-20UNF mounting studs accommodate reservoir wall thicknesses up to .75 inches Suitable for use with most hydraulic and machine lubricating oils Access to inside of reservoir is required to mount this style sight gauge Caution: Not recommended for use with steam, acidic fluids, caustic fluids and volatile fluids. If aluminum construction is selected for a water application, anodizing is recommended. Reservoir must be drained to remove dial thermometer or loss of fluid will occur