P. P. Inc. porcelain signals
 Porcelain Products Inc. came into being in 1927 through the merger of several
insulator manufacturers. Wet process insulators were mainly produced in a former
G.P. Co. factory in Parkersburg, WV.  In 1956 P.P. Inc. became an acquisition of
A.B. Chance Company.

  Reported styles: U-282, U-283, U-291, U-292, U-292A, U-293, U-293A, U-293B,     
U-295A, U-297, U-299, U-302

  Reported colors: yellow, green, white, brown, dark blue, cobalt, chocolate brown
Three U-283s. Incised on dome "PP" in rectangle.
Three U-293Bs. Incised on dome "PP" in rectangle.
The following are all U-292s. Ink stamped on dome "PP" over "-INC-" within
rectangle and all that over date. Most include an incised letter production code.
U-318 combo PP Inc and Knox.
Unknown U#s. Both are incised on dome "PP" within rectangle.