Founded in 1887 by D.M. Bare, Roaring Spring Paper Products has been an integral part of the Roaring Spring community for more that 130 years. Employing over 200 people, the company prides itself on remaining a family-owned, American small business. This book is ideal for use in labs and science classes. The 15# paper has a white original sheet and yellow copy sheet. The top white sheet is printed with 4 square/inch graph layout, and the canary sheet is unprinted. The book includes sheets of carbonless paper that can be removed and placed between the white and canary sheets. Sets are consecutively numbered 1-50 The front covers is made from durable 20 pt grey pressboard, and the back is 30 pt grey chipboard. The book is stapled and taped along the 11″ side. There are 50 sets per book. Proudly made in USA!