The small roller turns faster than the large roller, which takes longer to ride and is therefore slower. However, the small roller is easier to start with, and we recommend fitness on the floor.
We suggest using the large roller for more focused training for board sports to simulate waves, trails, and all exercises that require height (snowboarding, surfing, wakeboarding, kitesurfing, trampoline, volleyball, etc.)
At the request, we decided to add both rollers with "The Starter kit" so you can deal with all types of training.