The Montessori Potty
The Prepared Environment at How we Montessori,
Using a potty isn't necessarily a part of the Montessori approach to toilet learning. It may work to make the toilet more accessible by using steps or other adaptions. If you are interested in toilet learning the Montessori way I recommend Toilet Awareness and Toilet Leaning - The Montessori Approach. I also recommend articles at Aid to Life and Michael Olaf.