KONG Air Dog Squeaker Bone Medium Product Description Give them a squeeze. Special nonabrasive tennis ball fabric will not wear down dog's teeth. All squeaker units are recessed in rubber and covered with tennis ball fabric for safety. Available in size medium. Available in size medium. All squeaker units are recessed in rubber and covered with tennis ball fabric for safety. Special nonabrasive tennis ball fabric will not wear down dog's teeth. Give them a squeeze.