Place a balloon on the tube at the base of the Boom Tower. Pump the detonator, filling the balloon with air. As the pressure rises and the balloon expands, it presses into popping points on the inside of the tower’s two arcs, and — BOOM! — there’s a winner. Two units are provided. Balloons are not included. You can purchase 11″ or 12″ balloons for this game at your local store.