Model YBO-BSB2/SIL is an O Rated EN54-23 compliant addressable loop powered Base Sounder with integral Beacon, innovatively designed to give a range of tones and volumes with a maximum output of up to 98 dB(A) (±2 dB(A)) with low current consumption. The unit is designed to fit to the Standard Base (YBN-R/3/SIL) or the Isolator Base (YBN-R/3(SCI)/SIL) and can be fitted with any of the ESP SIL2 approved range of Sensors, Beacons or Remote Indicators. The unit can also be converted into a wall sounder beacon with the simple addition of a Cap (SI/CAP2). The sounder is Ingress Protection rated to IP21 and for internal use only. An Auto-Shutdown feature allows the user to set a fixed time within which the sounder or beacon will operate, before automatically shutting down, cutting noise pollution in the case of the sounder element.