Tau 2

Rolling Square designed the TAU 2 around a simple observation: emergency power banks only help when you remember to bring them. By reducing dimensions to keychain scale and including a magnetic charging dock intended for wall mounting near your entrance, they eliminate the decision-making that causes most backup batteries to sit forgotten in drawers when needed most.

The form factor resembles a thick key fob, attaching to existing keychains through an integrated loop that keeps it accessible without dedicated pocket space. When you arrive home or at an office, the magnetic dock accepts the TAU 2 automatically, maintaining full charge through passive habit rather than active planning. This design acknowledges human behavior honestly: we reliably touch our keys, so attaching power to keys creates power that travels with us.

Capacity provides meaningful emergency reserve rather than full recharges. The internal cell stores enough energy to restore a smartphone from critical levels to functional percentage, bridging the gap between dead battery and next opportunity to reach a proper charger. The included connector supports current USB-C devices, while the compact housing protects internal components without adding bulk that would make the keychain uncomfortable to carry.

Build quality uses materials that withstand the treatment keychains receive. Keys scratch against each other, drop onto hard surfaces, and endure pocket compression daily. The TAU 2 exterior resists these conditions while maintaining the clean appearance appropriate for a designed object rather than purely utilitarian gear. For travelers, commuters, or anyone who has experienced the particular frustration of a dying phone at the worst possible moment, it offers insurance that requires no conscious effort to maintain.