Precision Analytical Masses (ASTM Class 1) is recognized by the National Institute of Standards and Technology (NIST), the American Society for Testing and Materials (ASTM) and the International Organization of Legal Metrology (OIML) for its precision weights and mass standards. The weights can range from the very precise, highly polished one and two-piece stainless steel weights to 5,000 lb cast-iron weights.

The ASTM Class 1 weights are appropriate for calibrating high precision analytical balances with a readability as low as 0.1 mg to 0.01 mg. In addition, these weights can be used as a reference standard in calibrating other weights. These weights are highly resistant to corrosion thanks to an alloyed stainless steel and among the finest in state primary standards for manufacturing.

The class 1 precision weights are 1 g and larger, and are produced from two pieces of material: the body of the weight and the knob of the weight. This lifting knob is specifically designed for use with forceps, tweezers, and other lifting devices.

Key Features

• ASTM internationally recognized weight specifications
• Alloy 8 Stainless Steel
• Tolerances and design restrictions for each class
• Slightly recessed weight bottoms to limit contact with water
• Precise weight heads and necks allowing for sure grip to forceps or weight lifters
• Class 1 weights can be used to calibrate certain Class I and Class II balances and scales as specified in OIML R 76. Class 1 weights can also be used to calibrate Class 2 weights