Ertui is a traditional firecracker in China, commonly known as Double Ring, and also a traditional folk product. It is often used in festivals, weddings, commemorative ceremonies and many other occasions. It is based on the principle that the paper tube of double-fragrant firecrackers is divided into two layers to put gunpowder. The function of the lower gunpowder is to send firecrackers to the sky, and the upper gunpowder explodes in the air after 10 to 20 meters. Erkicker is a kind of firecrackers. Elki Kerr's powder is divided into two layers by cement or soil, and the back door at the bottom is not blocked tightly. The airflow generated by the lower gunpowder explosion broke through the back door and sprayed downward, generating upward thrust and pushing firecrackers into the air. At this time, the fuse just ignited the sealing powder at the upper end and quickly burned and exploded. Elki Kerr bloomed with a bang in mid-air, and fireworks quickly relied on gunpowder.