Kicking two feet means double-ring firecrackers. Northeast is called two kicks or double bells. It is a traditional folk product, which is often used in festivals, weddings, commemorative ceremonies and many other occasions. It is based on the principle of taking off when the impact force on the ground produces reaction force when the bottom powder explodes.

The powder of double-ring firecrackers is divided into two layers with cement or soil. The "back door" at the bottom is not tightly blocked, and the airflow generated by the lower gunpowder explosion "pinged" through the back door and sprayed downward. The downward jet of air generates upward thrust, pushing firecrackers into the air. At this time, the fuse just ignited the gunpowder sealed at the upper end, and it quickly burned-exploded, and the second kick blossomed in mid-air. Fireworks also rely on the rapid combustion of gunpowder-the thrust generated by the explosion.