At the same time, the fact that more than 60% of the enrollees continued to use the device over a period of more than six months indicates that voluntary use of the monitoring devices may be possible in industrial worksites. There were key aspects of the study that differ from usual use of hearing protection in hearing conservation programs (aside from the daily exposure monitoring feature). These differences include the use of cash incentives to encourage use of the device, and allowing the noise exposure information to be kept confidential and not shared with management.