When procuring base isolators, the most critical technical factor is the Vertical Load Capacity, which must align with the building's structural weight. You must also evaluate the Horizontal Stiffness and Damping Ratio (typically between 10% to 30%) to ensure the system can effectively absorb seismic energy. For Lead Rubber Bearings (LRB), verify the purity of the lead core, while for High Damping Rubber Bearings (HDRB), focus on the shear modulus stability. Ensure the Maximum Displacement capacity exceeds the predicted seismic drift of your specific geographic zone.