Electric vehicles are the main market for Romeo Power Technology, the Vernon-based lithium-ion battery pack startup. But the company is also using its know-how to make portable battery packs for individuals. On Thursday it introduced the Saber, a ruggedized 2.2-pound bar-shaped device the company says can quick-charge a smartphone 10 times -- or, with the right connectors, 10 smartphones at once. It can also recharge tablets, laptops and small drone aircraft as fast as a wall charger, the company said -- it's "like having a wall-socket in your pocket," said Dion Isselhardt, the company's chief product officer. The Saber itself requires two hours of wall time for a refill.