How long will the FT-28 Cool Cube™ last? L How long will the FT-28 Cool Cube™ last? The FT-28 when properly conditioned will last 94+ hours. Post navigationPrevious post: How long does it take to get the “VT-28” Cool Cube™ ready to hold my vaccine?Next post: How do I condition the FT-28 for use? Leave a Reply Cancel replyYou must be logged in to post a comment.