Yes, these rechargeable horns are very cool. Some are made to fit a
standard 16 oz soda bottle (to fit in the water bottle cage). You can
increase toot capacity by using a 1-liter bottle instead, but don't go
to a larger diameter bottle like a 2 or 3 liter as the burst pressure
drops with diameter but total energy stored goes way up. A 2 liter will
burst at around 160 to 180 psi with devastating force (and a report
like a car backfiring).

-Adam