Cando gel hand exercise ball, large cylindrical, black, x-firm cando gel squeeze ball hand exerciser for grip strength, dexterity, mobility, and fine and gross motor skills. Heat or chill for use in hot or cold therapy. Available in 6 color-coded resistance levels. Each level (firmness) available in circular or egg shape. Balls can withstand temperatures ranging from -76f to 167f. Large cylindrical – black – x-heavy.