Artwork needs to be supplied in CMYK print-ready PDFs for both sides.
the cards are 86 x 54mm; there's a 3mm bleed on all sides, and backgrounds should cover the bleed, while no important text should be within that area. The design includes template lines for safe area (the area guaranteed to be visible on the card), cut line, and bleed.
The address, QR code and mnemonic panels need to remain where they are, but the rest of the design is yours to alter. The front of the card has the same dimensions, but there are no design constraints. Neither side needs to have any ether.cards branding; the design is entirely white-label.
(template psd has been added)