I Have cat Which autopet model is suitable what does C & D series means ?

C-Series (model no - C20, C50, C70) - all these model are suitable for you. all C series mechanical performance remains the same but different technology for more control, convenience .

C-Series if for small size food kibble and most of the cat food brands food is partially soft & 3-7MM in size. D-Series is for hard & bigger size of food mechanically more powerful motors and conveyor is required.