Modulo Keys — Bitcoin Storage for the Long Term
Permanent. Offline. Yours.
Generate entropy directly in physical form. No software, no network, no manufacturing risk. SUS304/316 stainless steel — forged to outlast its owner by generations.
SUS304/316 stainless — the alloys trusted in nuclear reactors and deep ocean environments.
Multi-century durability. No corroding chips, no fading ink. This key holds information through time.
Survives extreme temperatures that would destroy paper wallets, electronics, and seed phrases.
Generate entropy in physical form. No software, no network, no intermediaries — ever.
Keys, Not Accounts
Generate your key in its permanent physical form — no transcription, no software, no supply-chain uncertainty. Just physics and steel.
Multi-generational bitcoin storage without intermediaries or third parties, celebrating Satoshi Nakamoto's original vision of transactional freedom.
For bitcoin, for nostr, for networks, for anything that runs on keys and requires entropy.
Material
High-quality stainless steel chosen for corrosion resistance that will endure for generations. The 256-bit key ships with a 4mm thick stainless steel protective case.
No corroding microchips, no dissolving paper or fading ink, no degrading data. This key holds information through time.
Security
No electronics or operating system means your private key is safe from hackers and malware by design.
Randomly assembling bits into the eight slots converts real-world entropy into a number that cannot be duplicated.
All 115 quinvigintillion+ possible bitcoin keys between 0 and 2256.
Technical Specifications
| Materials & Construction | |
| Material | SUS304/316 Stainless Steel — same alloys used in nuclear reactors and ocean environments |
| Case Thickness | 4mm steel walls — protective case included with 256-bit key |
| Electronics | Zero — fully offline, immune to hacking, malware, and electronic failure |
| Lifespan | Multi-generational — engineered for permanence across centuries |
| Cryptography | |
| Key Space | 2256 possible keys — 115 quinvigintillion+ unique combinations |
| Entropy Source | Physical random assembly — no software, no network, no manufacturing risk |
| 256-Bit Key | |
| Key Length | 133mm assembled |
| Diameter / Weight | 28mm · 357g |
| Threading | M6×1.0 |
| Case Dimensions | 141×60mm · 1,196g |
| 128-Bit MINI Key | |
| Key Length | 55mm assembled |
| Diameter / Weight | 14mm · 36.7g |
| Threading | M5×0.8 |
| Case Dimensions | 60×25mm · 107.8g |
Modulo and LEJR joined to develop privacy devices, a collaboration resulting in the first physical bitcoin private key.
Our purpose is to create beautiful, simple tools that give customers control, safety and security in form and function.
Own Your Security
Bitcoin price saves you 10%. Zero processing fees on Lightning.
Full system · Key + Case
133mm stainless key with 141mm protective case. 4mm walls. M6×1.0 threading. The complete Bitcoin private key system.
Compact system · Key + Case
55mm compact key with 60mm protective case. Lightweight at 36.7g. Perfect for a secondary key or minimal setup.
⚡ 10% Bitcoin discount applied. zero processing fees via BTCPay Server.
Invoice via BTCPay Server at lightning-mod.com · Lightning or on-chain Bitcoin · Zero fees, zero middlemen