The Aprilaire 4101 is a compatible part for the following humidifier models:
The Aprilaire 4101 Humidifier Float Chamber is a replacement knob and bolt assembly for Aprilaire humidifier models 445 and 448. The knob and bolt assembly attach the reservoir to the base of your Aprilaire humidifier and keep it in place. This Aprilaire float chamber features easy maintenance for your convenience. In addition, this part is made out of durable material to make it a long lasting fit in your existing Aprilaire humidifier.
Aprilaire 4101 Humidifier Float Chamber specifications: