Casio - FX-82MS. I bought it in high school, used it in University and now on my 4th year as a Professional Accountant. Haven't changed the battery once. : r/BuyItForLife
Flipkart.com | InfiDeals FX - 82MS Scientific Calculator Battery Powered 2 Line LCD Display Scientific Calculator - Scientific
Scientific Calculator 401Funtions with Case, Financial Calculators Large Display for School, Battery Solar Calculadora Cientifica for Students, Construction, Statistics, Engineering, Geometry - Walmart.com