The hole in the back make the user easier take out their cards.
Megnet makes the lead of holder won't open by itself.

Bean CARD Holder is easy to hold and open. the magnet keep the cap in the certain place and the hole in the back make the users easy to take their own card. Besides, the shape of this card is more ergonomic for holding,

Wan-Chan Joyce Lin
Link Upon Advanced Material Corp at Link Upon Advanced Material... Neihu District, Taiwan