May and June of this year I posted most of my Sterling Plastic Company Collection. Any low cost, made in the USA school or office supply item was made by Sterling Plastic. Rulers, Protractors, pencil boxes, slide rules and pencil sharpeners were made by Sterling Plastic. I did not post the plastic storage boxes. Here we have four great examples. Back left is the letter file small storage box model #274. To the right is the large letter file storage box, I believe the model is a #275. Up front are two check files model #273. These all work and are from the 70s or early 80s. If you are looking for these try and find ones with the red,white and blue labels still attached. Rulers are also sterling Plastic.