Aprilaire 4336 Istor Case and Manual Mode Label, For Use With: 56 Or 58 Humidistat, Includes: 46K istor and Manual Mode Dial Sticker manual mode istor automatic control uses either the manual mode istor or an outdoor temperature sensor (part number 8052). It needs one or the other to function properly. The can be used with the #56 or #58 digital control. Part includes 46K istor and manual mode dial sticker. We recommend that any wiring on your humidifier be completed by an contractor.