An insert for a drill bit is disclosed which includes an exposed surface having a contact portion adapted to periodically contact earthen formation. The carrier structure is composed of at least two releasably interconnected modules. At least one respective item in compact format is displayed above the selected item and at least one respective item in compact format displayed below the selected item. The inner cap portion is disposable and removably positioned within the bore of the outer cap portion. The holding arm is detachably and movably mounted in the holder during opening and closing of the centrifuge lid, and the holding arm and the holder are spaced via a gap space when the centrifuge lid is closed.