In summary, depending on the design an extractor can extract only, insert and extract, or insert and extract with a latch for positive locking to the board. Extractors that have a U-shaped design can both insert and extract, others can only extract the PCB. Calmark/Birtcher offers many PCB inserters/extractors for sheet metal or cold wall applications, in both nylon and aluminum, and designs that offer various mechanical advantages and support various PCB thicknesses.