I've done dozens of shaker cards in the past, but when I saw a technique that removes the bulk of the card I just had to try it. This card is a two way shaker, meaning that open or closed you can see the shaker.
Having less bulk in a card allows for easier mailing and a reduced risk of getting damaged while being tossed about in the postal system.
Any card maker with experience in shakers will tell you that there is nothing worse than finding out the time (potentially hours) put into making a shaker card was all for naught because of postal damage. While I personally love the dimension that a traditional shaker has, this technique is far more mail friendly.
Two-way shaker card with copic coloured winter penguin skating on glossy ice with Christmas twine accent.