Yellowstone County commissioners have approved a new clear-bag policy for attendees of events at First Interstate Arena at MetraPark.The policy, which was approved Oct. 8, prohibits all bags, backpacks and other carriers from entering the arena, except for ones made of transparent material that are smaller than 12 inches by 6 inches by 12 inches.In addition, attendees are allowed to bring in small clutch bags, one gallon clear plastic freezer bags, diaper bags and medically necessary bags.Diaper bags can only be brought in by a guardian with a child. Medically necessary bags can contain medication, pill bottles, ice to keep medication cold or other medical items.All items inside clear bags must be visible for security checks.