N-1041-C
https://www.sliderulemuseum.com/Pickett/Pickett_1041-G_FisherUniversalValveSizingRule_RobertNCurry.jpg
N-1041-GP
https://www.sliderulemuseum.com/Pickett/S486_Pickett_N1041-GP_FisherControlsValveSizing.jpg