Massage and cold treatment in one. Reduces in ammation and swelling from training, sports injuries, arthritis and more. After freezing the stainless roller ball, it stays cold longer than ice. It doesnﾒt melt so you can relieve muscle tensions without wet mess. Includes: Ergonomically shaped handle and stainless steel ball with cooling gel inside. Ball diameter 5 cm. Freezer time: max 5 hours per time.