The Duo 7-in-1 is a Pressure Cooker, Sauté Pan, Steamer, Slow Cooker, Rice Cooker, Food Warmer, and Yogurt Maker - all in one.
The Duo Plus 9-in-1 is a Pressure Cooker, Sauté Pan, Steamer, Slow Cooker, Rice Cooker, Food Warmer, Yogurt Maker, Sterilizer, and Sous Vide. New and improved features in the Duo Plus are EasySeal Lid and Easy Steam Release.
With the EasySeal Lid feature, the unit will automatically seal once the lid is closed. And with the Easy Steam Release feature, steam can be released just by pressing a button.
The Duo 7-in-1 has to be manually set to seal and release steam by turning the valve.