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