The Nike Dri-FIT Boys Slim Fit Performance Training Pants in Black, size Medium, are made of polyester material, and feature a pull-on closure and moisture-wicking technology to keep the wearer dry and comfortable during workouts. The sleek track pants style and solid black color make them versatile for various activewear occasions, while the machine washable fabric ensures easy care and maintenance. Perfect for young athletes looking for quality performance apparel from a trusted brand like Nike!