The 2.4GHz ISM band is available worldwide for unlicensed digital devices of many kinds, including WiFi, Bluetooth, and Zigbee. Congestion in this band increases every year, creating the potential for interference. The 900MHz band can only be used in USA, Canada, Brazil, Australia, and New Zealand. It is less congested. The longer wavelength travels further and works better in water environments. There is less bandwidth available, reducing the maximum number of DMX universes that can be delivered. The 5.8GHz band is available worldwide. Today it is less congested than 2.4GHz, but more products and systems are appearing everyday. The shorter wavelength reduces range, limiting usefulness in some wireless DMX applications.