 Consumer fireworks in the United States are limited to 500 grams (this was previously 200 grams until recent years) of composition and firecrackers may have up to 50 milligrams of flash powder.Reloadable shells are limited to 1.75" in diameter, and shells in pre-fused tubes are limited to 2".Any fireworks that exceed these limits are not considered consumer fireworks and need an ATF license.