The processes of mounting, inserting and coarsely aligning the specimen in the atom probe is common to most atom probe instruments. The sample needs to be placed in a puck, in order to be inserted into the atom probe. Samples prepared by FIB are usually held in a specially-designed sample holder that is compatible with SEM, TEM and APT. Needles prepared by electropolishing are clamped within a stub that can also be inserted into the APT puck. The puck can then be inserted into a slot on a carousel (which can hold multiple pucks).