• 51111-4770T Oil Sight Glass is the older series oil sight glass with "NO RED DOT" in the center of the oil sight glass.

• This 51111-4770T Sight Glass is approximately 1 inch in diameter and this oil sight glass has a "Rubber O-Ring" that fits snugly at the top of the thread line.

• This Sight Glass was used on the P series PS25, PV05A, PT03A was used on various brands of air compressors including both electric and gas powered oil lubricated single stage air compressor, 2 stage air compressors, portable air compressor, direct drive compressors and stationary air compressors as well as many oil free hand carry air compressors.