Countersunk head drive in rivets are made to sit flush in a countersunk/recessed hole and feature a center drive pin. These rivets eliminate the need for a setting tool as the center drive pin is hammered in to set the rivet. These rivets are generally used for truck and trailer applications such as in fiberglass trailer panels. Grip range is the amount of material the rivet will be going through, not the actual length of the rivet, which will always be longer than the grip range.