This 40" white, reusable, inflatable bag with a sand weighted base comes with five wet-erase markers so it can be used over and over. This product presents an opportunity for individuals who are reticent or unable to express themselves. They can write or draw anything that represents the anger they are feeling on the bop bag and then hit the bag to release the anger and aggression in healthy and safe ways. Not for aggressive play with older children. Bop Bag appeared on NBC television show "Outsourced". NOTE: We recommend using washable children's markers if you expect your bop bag to get a lot of use. To clean your bop bag try using 90% strength rubbing alcohol to remove the marker, or Expo White Board Care (or similar dry eraser cleaner).