The only revolving plank with small ball equipment that you really need is the following: small exercise ball. There are however many different revolving plank with small ball variations that you can try out that may require different types of revolving plank with small ball equipment or maye even require no equipment at all.
Swiss ball, stability ball, fitness ball, balance ball, fit ball, large and small exercise ball are all names for the same type of bouncy, colorful balls you see in practically every gym. They vary in size, are inflated with air but are puncture-resistant and are made of pliable soft PVC. They are used in exercise and training as well as rehabilitation and physical therapy. Originally known as the Swiss ball, these elastic balls were created in 1963 by an Italian plastics manufacturer called Aquilino Cosani.
Small exercise balls instantly angle you in the optimum position to obtain the best results from your abdominal workout. As well as a greater extension, they also give you a better range of motion so you receive a significant boost when crunching your abs. Compared to ordinary abdominal crunches, small fit balls are up to 408% more effective.
So it does seem that the smaller balls are the way to go for getting strong, defined and flatter abs because forward flexion and extension of the back is obtained. It works those deeper muscles as opposed to larger balls where your abdominal curl is not so effective. Investment in a small exercise ball seems to be the way forward for a deeper workout with those hard-to-reach lower abdominal muscles becoming more engaged compared to using the larger balls.