The Offset Process Technical Trade School Lessons Lot of 71939 Printing Lesson 2 Graining Plates, 6 Mac Webendorfer, 7 Offset Blankets, 8 Troubles on the Press, 9 Mechanical Adjustments, Lesson 10 Harris LSB & LSN, 12 pH Etches Gum. Booklets that measure 6 1/2 x 10 each.