One piece oil sight glass, the Monolith

Introducing the Monolith.

Our one-pierce design meets & exceeds new refinery standards.

Machined from a solid piece of acrylic.

To be clear, it's clear from the start.

Engineered for optimal visual oil analysis and inspection. Using an oil slight glass on your equipment can help to avoid a costly repair.

New design standard, same reliable oil sight glass.

The Monolith oil sight glass will be an early indicator of wear on the bearings, contamination problems and can help find the source of such problems. The oil sight glass alone will not prevent moisture from entering your reservoir or remove any water that has become emulsified in the oil. However, pump inspection regularly using oil sight glasses provides a visual inspection of the oil and a magnified view of the presence of sediment.

An oil sight glass is also known as sediment bottle, deb jug, and water finder to name a few. To this day, PK Machine brings you the first, the original and the best oil sight glass available anywhere and it is manufactured in the United States since 1962.

Used to monitor oil contamination, discoloration and water contaminate level, PK Oil Sight Glasses are:

  • Machined using a single piece of acrylic
  • Optical Grade Acrylic construction
  • Chemically compatible with gear, mineral and synthetic oils
  • Chemical and corrosion resistant
  • Operates to 200 degF and 300 psi
  • Available with multiple brass drain valve options


  • Visual oil condition monitoring with an oil sight glass by all plant personnel is an industry-standard way to spot a problem long before it becomes a costly repair. Transparent oil sight glasses mount to the drain of the lubricating oil sump with a threaded connection and include a drain valve for water removal. Immediate visual inspection allows users to take immediate action for the presence of free water, sediment, emulsified oil, or dark oil.

    Choose the right oil sight glass for you. Please call us if you have any questions at (530)878-4855.

    Monolith details box insert