Jumbo-Plus Ice Pack, 11" x 21", 2 Straps, 10/cs For large areas including the lower back, abdomen and chest. Contoured fit for knees, elbows and ankles. Sleeve material is polyester knit covering with elastic hinge connecting dual compartments. The replacement bladder is made of two-layer construction with nonwoven polyester-rayon outer covering, vinyl inner layer.