Casio 27CL-11 / 27CL-12 Manual — Module 27

Two owner's manual PDFs for the Casio module 27, each a different scan (English included). Casio fitted it in 4 models, including the 27CL-11 and 27CL-12 — the full list is below. Casio's spec sheet lists one 392, with 12 months of battery life and accuracy within ±15 seconds a month; the module first shipped in Oct 1977.