Serial Bagmakers has designed these frames herself so they are an improvement to the ones you can find on the market. She designed these curved wallet frames to be slightly curved and by that they are more forgiving around the hole (you can cut your hole slightly bigger so you do not see the edge of your fabric).
They have closed ends for a neat finish (no need to finish the ends of your wallet).
The latch is a big hollow oval to create that special form without it being too bulky or heavy.