SatoshiLabs ships the Trezor One — the world's first Bitcoin hardware wallet. Created by Czech developers Marek "Slush" Palatinus and Pavol Rusnak, the Trezor introduced the concept of storing private keys on a dedicated offline device, away from internet-connected computers.
Before Trezor, securing Bitcoin meant paper wallets, encrypted files, or trusting an exchange. The Trezor One created an entirely new product category and proved that self-custody could be both secure and user-friendly. Every hardware wallet that followed owes something to this device.
Wikipedia: Trezor