The G635 Series front mount closed circuit sight gauge provides 270° of viewing 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). The oversized gauge body allows a deeper recess of the sight glass for maximum protection of the sight glass against damage. Standard Features: Centerline length of 5 inches Front mount 1.25 inch SQ body machined from aluminum bar stock 270° of viewing the fluid level (.91 inch front and .50 inch side width windows) Viewing enhanced by redline on white background integral to sight glass HIGH-LOW markings on front face of 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 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.