A tie-down apparatus comprises a cam buckle disposed intermediate each end of the tie-down apparatus, a first strapping material having a first end engageable with a first end of the cam buckle and a second strapping material having a first end engageable with a second end of the cam buckle. The forming ring is placed between the draw pad and die center, and is used to apply a force on the material during the shell lid forming process. The at least one retaining leg is configured to contact tissue on the second side of the defect to retain the covering member and has a first configuration for delivery and a second configuration for placement on the second side of the defect. The touch sensor controller is operable to apply a respective voltage pulse simultaneously to each of the first plurality of electrode lines, measure a respective signal at each of the second plurality of electrode lines, and detect a touch based on the measurement of the respective signals.