For users holding $50k+ who want maximum security. The QR workflow adds 30 seconds per transaction vs USB, but eliminates entire categories of attacks. Works with MetaMask (with QR plugin).
Keystone 3 Pro
Air-gapped hardware wallet. No USB, no Bluetooth, communicates via QR codes only.
Higher-end hardware wallet that eliminates USB/Bluetooth attack surface. Transactions are signed by scanning QR codes back and forth between the device and your phone. Larger screen than Ledger/Trezor.
Pros
- Completely air-gapped (no USB attack surface)
- Large touch screen
- Built-in fingerprint sensor
- Open-source secure element
Cons
- Slower workflow (QR scanning)
- More expensive
- Smaller ecosystem than Ledger