This is our most popular scrimmage vest. Used widely in schools and in physical education classes. Features large arm holes for easy on, easy off and unrestricted movement. Durable, 100% nylon mesh helps keeps participants cool. Elastic waist band provides a comfortable fit. Available in 3 sizes: Sizing Suggestions: Elementary age students will probably use mostly small with some Medium/Large needed Middle school age children through High School Age will need mostly Medium/Large and some X-Large. Sizing is designed primarily for children.