High-Performance Replacement Battery for MSI Modern 15 and Summit B15 Laptops Restore your MSI Modern 15 or Summit B15 laptop to optimal performance with this premium 52.4Wh Li-ion replacement battery. Specifically designed for MSI's business and productivity series, this BTY-M491 compatible battery delivers reliable power for work and creative tasks. Features stable 11.4V output and high-quality Grade A cells for extended battery life.