Buyers must prioritize particle size distribution (mesh size), as it determines the application; for instance, 1-3mm granules are ideal for running tracks, while 0.5-1.5mm is better for artificial turf infill. Additionally, ensure the purity level is high, with a steel and fiber content of less than 0.01% to prevent injury in flooring applications. The polymer content (SBR, EPDM, or Natural Rubber) should be verified to ensure the material meets the required elasticity and UV resistance standards.