Vials used for obtaining an aliquot of a biological sample are provided. The switch unit includes a main switch for switching data of a fixed length and an interface having a first buffer for an input of the main switch and a second buffer for an output of the main switch. Depending on user selections, identified portions of the audiovisual presentation may be skipped andor muted during play. The vacuum device also includes a filter for air leaving the device which may include filter material in a filter housing over which a vacuum bag may be placed.