You can do this course with the Crystal Bowls you used for our Level 1 Course.
You don't need to buy any extra Crystal Singing Bowls.
However, if you want to dive in deeply, expanding your set of bowls would be beneficial, and at minimum suggest a set of 4 bowls (C E G B) to be able to create 1 major and 1 minor triad plus releasing and harmonizing intervals.
A set of 6 bowls C,D,E,F,G,A, will allow you to be able to create a mixture of major and minor triads plus releasing and harmonizing intervals.
You can purchase two additional bowls: B and high C (in the same octave) to complete the chakra set and give you a full octave range - which will allow you to expand on the sounds available to you and also get the most from this course.
Suede covered mallet
Mallet with rubber ball – especially for playing frosted bowls