Specifications:
12MM-17 Pieces (within a circumference of about 16.5cm) ------ lean for girls or teenagers
15MM-15 Pieces (within a circumference of about 17.5cm) ------ for adult men
18MM-13 Pieces (within a circumference of about 17.7cm) ------ for overweight / strong men
20MM-12 Pieces (within a circumference of about 18cm) ------ for higher fat men
