This is an official disc that can be used in NDA (National Disc Dog Association) competitions. The hardness is in the middle of the 5-level scale. The size is approximately 22.3cm in diameter. It's for dogs, so it's safe for your dog, and you can use it for throwing practice, etc. It is new and unused, but there may be fine scratches on the surface due to home storage. Please purchase only if you understand this.