The non-slip processing on the inside makes it difficult to slip off even during sports! Muscles vibrate when they receive impact. The body tries to suppress this unnecessary vibration, which can lead to a loss of stamina. Wearing arm sleeves compresses the entire arm, suppressing unnecessary muscle vibration and helping to prevent fatigue. Set of both arms Black Brand new, unused Available in 3 sizes: S, M, L. *Please comment your size when purchasing. Sizes (forearm circumference) S: 22-25 cm M: 25-28 cm L: 28-31 cm Due to the size restrictions of the mail service, the outer box will be folded for shipping. Thank you for your understanding. Thank you for viewing. Please feel free to comment if you have any questions!