Seat Sack offers a Medium 15 Inch storage chair pocket for classroom organization that features a durable cotton/poly laminated fabric that is certified flame-resistant and machine washable. The Black Seat Sack has a 10 inch deep pocket and a 2 inch gusset that offers ample storage space to accommodate books, papers, school supplies and more. Fits chairs that measure 12.5" or less along the very top and widens to 15" at the pocket. Perfect for classroom storage, teaching organization and behavior management.