The Skuttle 45-SH humidifier is a drum type bypass style humidifier that can be installed on either the supply or the return duct system of your home or office. This is a very reliable model that is extremely popular with our clients. You will find the most common parts for your Skuttle 45-SH on this page. The humidifier filter on your Skuttle 45-SH humidifier must be replaced at least once per year for optimum performance and to increase the life of your humidifier and heating equipment.