A revolutionary new signal horn that can be recharged with a ball compressor or a 9" mini pump for partial refills. Holds up to 150 lbs. of air pressure and unlike compressed gas signal horns, will not freeze in cold conditions. This environmentally friendly horn is 100% ozone safe. And it's rechargeable, not disposable, so each time you refill, you recycle. Sold with or without a pump, individually or by the case of 20.