Circular Teaching Folding Device comprises two bodies, where the first Body circumference is the central device, and the second body is associated throughout the length of its Periphery by a Hollow taffeta Cloth Tube filled with sand.

摘要

Circular Teaching Folding Device comprises two bodies, where the first Body circumference is the central device, and the second body is associated throughout the length of its Periphery by a Hollow taffeta Cloth Tube filled with sand.