A transfer set generally includes an outer sleeve configured for connecting aninner sleeve to a vial such that a passage of the inner sleeve is disposedabove a stopper of thevial. The transfer set further includes a cap configured for insertion intothe outer sleeve suchthat the cap is connected to the outer sleeve and is detachable from the outersleeve viarotation of the cap relative to the outer sleeve. The cap has an interiorspace and a cam disposedwithin the interior space, wherein the inner sleeve, and a spike within theinner sleeve, extendinto the interior space when the cap is connected to the outer sleeve, andwherein, as the caprotates relative to the outer sleeve for detachment of the cap from the outersleeve, the caminteracts with the follower to translate the spike toward the stopper forpuncturing the stopper.
