When sourcing plastic paving grids, the most critical factor is the Load-Bearing Capacity, which should range from 200 to 500 tons per square meter depending on whether it is for pedestrian or heavy-vehicle use. You must verify the Material Composition, prioritizing 100% recycled High-Density Polyethylene (HDPE) or Polypropylene (PP) for UV resistance and chemical stability. Additionally, check the Wall Thickness (typically 1.5mm to 3mm) and the Cell Height (30mm to 50mm), as these directly impact the amount of gravel or grass infill required and the overall structural integrity.