ROLP/RL/R/D RoLP Solista Sounder Beacon – Red LED, 9 28 V dc. Dual alert and alarm functionality are just a few of the leading specifications that allow this range of sounder beacons to be a popular and reliable solution for users. Predominantly used as a fire alarm, the RoLP sounder beacons provide a convenient, versatile and rugged solutions for industrial and commercial installations. Often, beacons are being used to replace audible alarms, this is because a combined sounder beacon allows for both audible and visuals through one single installation point.