The LSP701 Series low pressure aluminum sight plug has a clear glass sight with 4-bolt flange mounting pad. The sight plug installs through a clearance hole and utilizes a flange gasket compressed uniformly with four socket head cap screws to create a low profile assembly. Access to inside of reservoir is not required. Box quantities may apply. Standard Features: Sight diameters from .81 to 1.81 inches Clear glass sight Body machined from aluminum bar stock (4) Socket Head Cap Screws Pressure & Temperature Ratings: Maximum operating temperature up to 250°F (121°C). For applications requiring maximum operating temperatures in excess of 250°F (121°C), consult factory for available options. 10 psi (69 kPa) maximum operating pressure at 69°F (20°C) Caution: Not recommended for steam applications. Scratched glass significantly reduces the pressure rating of the sight plug.