When evaluating 9 shots fireworks cakes, buyers must focus on the tube diameter (inner bore size), which directly determines the explosion height and effect radius; common sizes range from 0.8 inch to 1.5 inches. Additionally, verify the Net Explosive Content (NEC) or powder weight per shot to ensure the intensity meets your market's expectations. The duration of the display (typically 15-30 seconds for a 9-shot cake) and the firing pattern (vertical, V-shape, or W-shape) are also critical for defining the product's visual impact.