Natural Agate Liner: This lab milling liner adopts Grade A natural agate with 7.0-7.2 Mohs hardness, strong wear resistance to deliver impurity-frees grinding results for mineral and chemical sample testing. Precision Matching Leakproof Sealing Lid: Liquid evaporation and powder spillage distort your wet-dry milling test data. Custom-fit matching lid forms tight enclosure, blocks cross-contamination, liquid loss and dust overflow during high-speed planetary grinding for university labs. Smooth Residue-Frees Inner Wall: Polished seamless inner surfaces minimizes materials buildup, cutting post-test cleanup workload for daily industrial sample preparation work. Heat Resistant Physical Structure: Tested anti-shock agate body holds stable under pressure and high temperature, no cracks or deformation after long continuous milling cycles for materials research teams. 4 Standard Capacities: Available in 50mL,100mL,250mL,500mL four sizes, compatible with mainstream planetary ball mill equipment to match small and medium lab experiment scales.