Plastic Visual ASD Behavior Keyring (Picture Communication Symbols) Uses only high quality picture communication symbol images by Mayer-Johnson (used with permission). These are the most common visual symbols to be used to support the learning and development of those with learning disabilities, and therefore will be the easiest for individuals to understand and begin to implement. Made from plastic to ensure durability. All corners are rounded to reduce the likelihood of scratches. Symbols are 7cm square - large enough to see easily but small enough that they are convenient and can easily be stored in your pocket. Symbols are held together on a sturdy binding ring, making it easy to change the order of the symbols or just take some out with you if you only need some of them.