Better as a training reward then a ball. The Franklin Glow in the dark street hockey puck lets you contorl how much running your K9 gets during training. toss it flat for short burst, not wasting your dogs energy that could be used for training or throw it and let it roll using as much energy as your dog is capable. Not to be used as a chew toy. 
Specially blended glow-in-the-dark PVC puck