Specifications: Material: Zinc alloy, glass. Colour: silver. Thread size: G1 / 2. Thread diameter: 16 mm. Thread outer diameter: 21 mm. Suitable for: Air compressor. Product function: The actual * oil in the position of the liquid level in the oil tank can be placed on the window glass of the tank to assess whether the * oil meets the operating conditions. Dimensions: 27.5 x 18 mm / 1.08 x 0.71 inches (diameter x height). Weight: 47 g. Features: You can read the oil level in the middle of the tank correctly and easily. The outer diameter of this oil levelling glasses with recessed hexagonal design. The seal is done with an O-ring on the circumference. This is mainly used to check the oil level of the pump in the air compressor. Package includes: 2 x air compressor metal G1 / 2 inch oil display glass with thread