The Ngrave ZERO works with the LIQUID app by means of QR codes. When transactions are originated in the app, they are signed by the ZERO's QR scanner. The ZERO, in turn, generates its own QR code, which needs to be signed by the app before the transaction is sent. In doing all these, communication with the online world is reduced to zero, hence the name. This ensures that the digital assets stored in the wallet are entirely secure.