A prop with a hollow, circular shape, almost like a sibling of a foam roller that works wonders by helping improve stretching, release tension, and increase flexibility. This is one of the yoga tools that many people use, and it's made for everybody, especially the yoga novices.
Difficulty : ★ ★ ★ ☆ ☆
Stamina : ★ ★ ★ ☆☆
Strength : ★ ★ ★ ☆ ☆
Stretching : ★ ★ ★ ★ ★
Calmness : ★ ★ ★ ☆ ☆ 