Those are finger slits. Think of them like you do training wheels on a bike. Just like training wheels are not necessary for the bike to fully function, the finger slits do not need to be used to gain the full benefits of HandBand Pro®.
There are finger slits on both sides so they are universal. You may put your pointer and pinkie finger through the holes, or you can use just one finger. If you put two fingers through and notice a gap between your palm and the grip, switch to just your pinkie finger through the slit. See how to customize them here!