Borobee (Material: Boronoki) Thickness: 1.0 inches (2.5 cm), Length: 15.7 inches (40 cm), Weight: Lightweight, Hardness: Soft (Suitable for beginners to advanced users); Medium size of hollow bee in total of 3 types. Borobi Medium 15.0 x 15.0 inches (38 x 2.5 x 38 cm), Large 15.7 x 15.7 inches (40 x 2.5 x 40 cm), Medium 1.0 inches (42 x 2.5 x 42 cm).