Cup D: Reliable and safe Helo Cup D sauna heaters are an excellent choice for traditional Finnish type sauna. These compact wall mounted heaters are designed for domestic small and mid-size sauna rooms. They are easy to assemble and easy to use with built-in timer and thermostat or with separate control unit. With the built-in timer you can pre-select the time when you want the heater to be turned on, max. 9 hours beforehand. The running time is 3 hours Cup STJ: Reliable and safe Helo Cup STJ sauna heaters are an excellent choice for traditional Finnish type sauna. These compact wall mounted heaters are designed for domestic small and mid-size sauna rooms. They are easy to assemble and easy to use with built-in timer and thermostat or with separate control unit. With the built-in timer you can pre-select the time when you want the heater to be turned on, max. 9 hours beforehand. The running time is 3 hours.