Description:    TDS-966 Digital ATC Pen-type TDS Meter Aquarium Water Total Dissolved Solid Tester 0~9990ppm    Features:   Automatic Temperature Compensation (ATC). Compact and pocket-sized design. Easy to use and provides a quick measurement. High accuracy with ±2% Full Scale. Factory Pre-calibrated. Data hold function and auto power off. Wide range of applications in water quality testing. Batteries included.   Specifications:   Measuring range: 0 ~ 9990 ppm (mg\/L) Resolution: 10 ppm (mg\/L) Accuracy: ±2% Full Scale (F.S.) LCD Display: 4-digits Automatic Temperature Compensation : 0 - 50  C (32 - 122  F) Operating Temperature: 0 - 50 C (32 - 122  F) Power: 2 x 3 V (CR1632) Button Cell Batteries (included) Dimension: approx. 147 (L) × 27 (W) × 18 (D) mm (5.79' x 1.06' x 0.7' inch) Weight: approx. 42 g   Packing includes:   1 x Pen-type TDS meter 1 x Mini Screwdriver 2 x 3 V (CR1632) Button Cell Batteries 1 x Instruction Manual  Details pictures: