Casio GT-007 / GT-007B Manual — Module 1815

Three owner's manual PDFs for the Casio module 1815, each a different scan (English included). Casio fitted it in the GT-007 and GT-007B. Casio's spec sheet lists one CR2016, with 18 months of battery life and accuracy within ±15 seconds a month; the module first shipped in Jun 1998.