XUEMEI This scale weights are designed with high precision and have a permissible error of +/-0.003g. Perfect for all your weighing needs STAIN-LESS STEEL CALIBRATION WEIGHT: Crafted of high grade carbon steel for extra durability and has a chrome finish for a sleek look. Compact design for easy access and convenience. This calibration weights construction made of heavy duty steel and it is durable and rust free for long lasting use PORTABLE WEIGHING SCALE: This Pocket sized weights are convenient and portable for the user. A compact design that firmly secures and protects the calibration weight and makes it easy to storage. The contains up to 1pc of 500g Scale Weight WIDE APPLICATION: Perfect for commercial, industrial, lab, or educational calibration purposes to ensure the most consistent weight readings on many digital scales. Also professional used for Jewelry, herbs, gems, labs, home, commercial or educational purposes for consistent weight reading SCALES PRECISION ACCURACY: Accuracy is the most important quality for scales and so there are methods for testing and calibrating weighing equipment. This is Nickle Plated accurate calibration for most precision weighing scales accuracy for your personal and professional use