Interleaving & Carbon-Backed duplicates. Duplicate paper, carbonless white SALESBOOK™ (3.50 x 5.63) has 12 lines. Original copy is printed in black and the duplicate in red. Cardboard wrap-around cover prevents multiple copy write-through. Duplicate interleaving carbon, SALESBOOK™ (3.50 x 5.63) has 11 lines. Original copy is printed in black and the duplicate in red.