This disclosure enables various threading devices (e.g., suturing devices) that can sequentially send a plurality of carriers (e.g., needle caps, sleeves) to an object (e.g., animate, inanimate, human tissue, organ tissue, heart tissue) or sequentially receive a plurality of carriers (e.g., needle caps, sleeves) from an object (e.g., animate, inanimate, human tissue, organ tissue, heart tissue). For example, some threading devices can sequentially send some carriers in a relatively rapid succession or some threading devices can sequentially receive some carriers in a relatively rapid succession.