The Industrial, Scientific and Medical (ISM) radio bands were originally reserved internationally for non-commercial use of RF electromagnetic fields for industrial, scientific and medical purposes.
The ISM bands are defined by the ITU-T in S5.138 and S5.150 of the Radio Regulations.(see external link below). Individual countries' use of the bands designated in these sections may differ due to variations in national radio regulations.
In recent years they have also been used for license-free error-tolerant communications applications such as wireless LANs and Bluetooth: