Rice Lake Cast Iron ASTM Class 7 Painted Slotted Interlocking Test Weight, 5lbs Mass U.S. customary slotted, interlocking test weight for use with weight hangers Painted cast iron weight has chip-resistant paint that resists corrosion and conforms to NIST Handbook 105-1 standard Sealable adjusting cavity for adjusting total weight Meets American Society for Testing and Materials (ASTM) E617, Class 7 specification for rough weighing operations in physical and chemical laboratories, and for force-measuring apparatus