K&E 68 1892 (4158) --- 10" All Plastic Mannheim Slide Rule
From the collection of Clark McCoy
The 4158 replaced the 4058 series. It was named the "K-12 Prep". It is all plastic. The trig scales were brought to the front side. There is no printing on the rear of the rule. The model number of this rule was changed to 68 1892 in 1962 and was a major seller for K&E into the 1970s. The 68 1892 is shown in catalogs from 1962 to 1972.
Right end of rule in clear plastic case. Case has a pocket on the rear of it for instruction sheets.