The oil drip calibration disc (regulator disc) fitted into the recess in the top of the regulating valve screw of both the early style of Best +Lloyd oil pump , with the tubular oil sight glass, and the later type with the 36 mm diameter disc type oil sight glass .
Suitable for such pumps where the original disc was the non-metallic type
The disc is engraved and has an Ivory hue
For pre-1922 pumps, consider using disc part number 64-462
