The Bauer Slivvver Roller Hockey Puck weighs 4.4oz making it heavier than a traditional roller puck. The aerodynamic design allows the puck to stay on the playing surface and keep it from rolling up on end, bouncing, or sliding off your stick. Using hard, hi-density runners fuse-welded into the body of the puck creates a softer feel. The Bauer Slivvver Puck is mandated by the IIHF during the Inline Hockey World Championships.