Just Pee Chee Keen

Every Fall starting when I was a kid in junior high school, besides new shoes and some new outfits I began the school year with a new notebook, new dividers and plenty of lined notebook paper. I also always got a brand new "Pee Chee" folder. I loved these folders and just seeing one brings back fond memories.

Wikepedia says this:

The yellow Pee Chee All Season Portfolio was a common American stationery item in the second half of the 20th century, commonly used by students for storing school papers. It was first produced in 1943 by the Western Tablet and Stationery Company of Kalamazoo, Michigan. Pee Chees were later produced by the Mead Corporation.
These relatively inexpensive folders were made of card stock and had two internal pockets for the storage of loose leaf paper. The pockets were printed with a variety of reference information including factors for converting between Imperial and metric measurement units, and a multiplication table. The folders had fallen out of general use by the 2000s, and are no longer being produced.
The illustrations on Pee Chee folders changed occasionally over the years, but usually depicted high school age students engaged in sports or other activities. The major difference from the Pee Chee and other paper folders were the inside pockets. Pee Chee had pockets located at the sides, not the bottom, which prevented the contents from falling out if the folder was inadvertently stored upside-down.