The SIP-HU is a heater unit from Optex which is specially manufactured to be used for the SIP series (1PC). The SIP-HU heater unit is highly constructed for use within colder climates to help operate the SIP in temperatures of -40°F. The SIP-HU heater unit also consists of a lightweight size and easy installation process and is able to keep the system fully functioning on even the colder days.