Thus is the perfect way to store your A2 cards ! Makes it easy to find what you need and see what you have.
An A2 card is one of the most popular cards. it is 4.25" x 5.5". This is exactly 1/2 of a 8.5 x 11 paper, a standard size in the US
A lot of pre-made card forms are in the A2 size. So this form of organizer makes perfect sense.