This year, bear sightings have increased further, so I think countermeasures are necessary. When firecrackers are placed in a tube and ignited, the sound of the firecrackers is amplified compared to just setting them off. The tube size is approximately 18mm. Comes with a waterproof firecracker case. As this is a handmade item, there may be minor scratches or dirt. Please use at your own risk.