The Helios TSSW 3 is a built-in transformer designed for installation in fuse boards, supplied without a housing. It includes a base ring and terminal strip to facilitate secure and easy mounting. The transformer offers five selectable voltage outputs — 0, 80, 130, 170, and 230 volts — enabling accurate speed control of fans in ventilation systems. This compact unit is ideal for panel-based installations where space efficiency and reliable operation are essential.