ECOBLAST is a rechargeable AIR horn - just pump in new AIR with a bicycle hand pump, a compressor or at your local service station | Suitable for marine use, industrial safety, sporting events Etc. | Uses plain normal AIR - not gas. Easily rechargeable for free | Safe for the environment - uses AIR only, no harmful gas | Never have to buy a refill cannister | Recharges via a recessed valve in the base of the horn | Easily refills with the mini air pump included in the kit, any bicycle pump, air compressor or tyre pump at your local service station | Horn has a plastic base cover to prevent any rust rings on surfaces | Powerful 115 decibel blast | Can be safely stored - no harmful or dangerous gas. Just AIR | Operates in all weather and temperature extremes | Includes Mini Hand Pump to recharge, over and over again