The STB2/3/4 is a customisable visual signal featuring a tower of 2/3/4 AlertAlight L101 type beacons. Each beacon position can contain either a Xenon or high output L.E.D. light source. It can operate in DC or AC voltages. The STB2/3/4 assembly features a pre-wired junction box and cable loom enabling the end user to determine beacon type and position during installation.