pocket letter scale

The text on the clip of the cover reads: Universal USA ®. On the side of this compact pen shaped little letter scale the following is printed:
Lufkin Typewriter Company, D.C. Satterwhite, 505 South First Street, Lufkin, Texas. NE 4-9113 NE 4-9124, 30 Years Of Faithful Service.
The chart has a rate of 4c per ounce for First Class. This was valid in the period from August 1 1958 till January 7 1963. The scale has a capacity of 8 ounces. Per ounce a subdivision stripe of measure is given. The postal rates for First Class, Air Mail, and Parcel Post are on the chart. Also the texts "Not Legal for Trade", MDSE and "Made in U.S.A." are printed on the chart. Below some more pictures of this short pen shaped letter scale.