How long will the BT-28 Cool Cube™ last? L How long will the BT-28 Cool Cube™ last? The BT-28 when properly conditioned will last 68+ hours. Post navigationPrevious post: How long will the BT-08 Cool Cube™ last?Next post: How long does it take to get the RT-03 Cool Cube™ ready to hold my vaccine? Leave a Reply Cancel replyYou must be logged in to post a comment.