Carlisle 401055 Crystalon Stack-All Tumbler, 9.5 oz, Rose, Plastic (Case of 48) Tumbler has a ribbed exterior that provides grip Dishwasher safe Tapered sides enable stacking for organization and storage Internal lugs prevent stacked tumblers from jamming SAN material is rigid and break resistant, and is BPA-free to address food safety concerns raised by FDA and other organizations