These handy blind holders are used by custom car builders to hold sheet metal parts before final welding. Very easy to use. Drill a 1/8″ hole through both pieces and insert fastener. Each one provides nearly 20 lbs holding power and has a grip range of up to 1/4″. A side-grip fastener is included for edge work For panels with flanged edges, use the C-panel holders (reach is 2″, opening is 3/4″).