1PC M39x2 Metric Male Aluminum Oil Level Sight Glass Window — Hex Head — for Air Compressor Gearbox Why this part matters Provides a fast, reliable way to monitor oil level inside gearboxes, air compressor housings and similar enclosures without disassembly. The integrated sight glass window lets you visually confirm oil presence and approximate level at a glance, reducing downtime and preventing damage from lowlubricant conditions. Compact, durable design with a hex head makes installation and removal simple using common hand tools. Key benefits Quick visual inspection: See oil level without opening the system. Simple maintenance: Install or remove with a wrench via the hex head for routine checks or replacement. Light and corrosionresistant: Aluminum construction resists rust and keeps the part lightweight. Main features and attributes Quantity: 1PC Thread: M39x2 (metric male thread, 39 mm diameter with 2 mm pitch) Material: Aluminum body Feature: Integrated oil level sight glass window for visual oil monitoring Head type: Hex head for easy tightening and loosening Intended application: Air compressor gearbox and similar oilfilled housings How it solves common problems Prevents overfilling and underfilling by enabling visual oil checks without opening the gearbox. Reduces inspection time during routine maintenance—saves labor and minimizes exposure of internal components to contaminants. Lightweight aluminum construction makes it suitable where metal compatibility and corrosion resistance are important. Typical applications / use cases Air compressor gearbox: Monitor oil level in compressor gear housings to ensure proper lubrication and extend component life. Small industrial gearboxes and pumps: Fit into enclosures that accept M39x2 male fittings for easy oil level verification during service checks. Custom machinery and retrofits: or add a sight glass on machines with compatible M39x2 threaded ports to enable visual oil checks. Installation and usage notes Ensure the mating port accepts an M39x2 metric male thread and that thread sealing method (thread sealant or tape) is appropriate for your application. Tighten the hex head with a correctly sized wrench—do not overtighten to avoid damaging the sight window or threads. Inspect the sight glass periodically for clarity and sealing integrity; if the window becomes scratched or compromised. includes One (1PC) M39x2 metric male aluminum oil level sight glass window with hex head, as described above. Compatible environments Designed for oilfilled housings such as air compressor gearboxes and similar enclosed lubrication systems that accept an M39x2 male fitting. This replacement sight glass offers a straightforward, durable solution for visual oil level monitoring in compatible air compressor gearboxes and related equipment.