nd Power Wrist Strengthener Ball Color tier size (length * width * thickness) Yellow (8 ~ 15 lbs) 208cm x 0.64cm x 5mm Red (15 ~ 35 lbs) 208cm x 0.88cm x 5mm Black (25 ~ 65 lbs) 208cm x 1.5cm x5mm Purple (35 ~ 85 lbs) 208cm x 2.3cm x 5mm Green (55 ~ 125 lbs) 208cm x3.3cm x5mm Attention: The resistance value is for reference only and may have some errors, which is a normal phenomenon Material and craftsmanship issues cannot be avoided, and there may be slight indentations and scratches on the product. Please note that there are default imperfections when purchasing