The G650 Series vented oil gage utilizes an adapter union fitting to connect the base of the oil gage to the reservoir. This construction offers advantages when installing oil gages in confined spaces by not requiring disassembly of the gage base. The viewing window and shield do not rotate during installation of the oil gage. The viewing window still has 360° adjustment for optimal orientation to view fluid after installation. The sealing gaskets are contained on both their ID and OD to facilitate trouble-free assembly after on-site repositioning of the viewing window. Standard Features: .69 inch SQ base Machined from brass bar stock Adapter union fitting between reservoir and gage base Reservoir thread connections of 1/8, 1/4 or 3/8 inch NPTF .39 inch wide viewing window, length varies from 1.33 to 7.33 inches depending on gage selected 360° adjustment of viewing window Suitable for use with most machine lubricating oils Temperature Rating: Maximum operating temperature of 250°F (121°C) with standard Buna N seals. For applications not compatible with Buna N seal material, consult factory for available options and corresponding temperature ratings.