The Oil Level Indicator (OLI) was developed in response to the need for maintenance professionals to gauge the oil level inside large tanks, gearboxes, and reservoirs. When water contamination is not a problem or when a regular Kabir Oil Sight Glass is already installed at the drain port, the Oil Level Indicator can be utilized to monitor oil levels. The OLI is a clear acrylic tube with NPT threads at each end. Red and green Buna O-rings are included with the OLI to mark upper and lower limits, or to designate running oil level and idle oil level. It can be installed with the optional breather* at the top NPT port as seen on the Kabir Oil Sight Glass and Level Monitor. If the user requires a closed loop, the NPT can be used as a connector port to feed back into the system. Operators can visually monitor the oil for dirt and debris and take appropriate preventive action.