Made of rubber, this dog ball is tough, teeth-gentle and safe for daily play. Motion-activated: touches to start, runs 1 minute then stops (restarts with a touch) for safe self-play. One button switches 2 modes (vibrating/rolling) with unpredictable, prey-like paths for exercise and mental stimulation. Usb-rechargeable (no batteries) with hours of play per charge. If your dog is hesitant, place a treat/stick in the cover for 3-5 minutes first. Suitable for indoor/outdoor use (rolling mode works poorly on thick rugs) IP54 water-resistant against saliva/splashes. Set includes 2 rubber and 2 baseball fabric covers for durability and varied play. 1-year replacement guarantee for malfunctions/quality issues.