The Stamina Booster is a sleek, cylindrical device with a metallic outer shell that features a subtle brushed texture, giving it a high-tech yet utilitarian appearance. It has a glowing blue LED strip running along its length, indicating its active state, and a series of small vents for heat dissipation. The device is compact, fitting comfortably in one hand, with a rubberized grip for secure handling. The top features a small, circular interface with a digital display that shows remaining charge in a minimalist, futuristic font.