Sennheiser RI 410 Battery - Replacement for Sennheiser BA300 Headphone Battery (150mAh, 3.7V, Lithium Polymer) Replacement Sennheiser RI 410 Battery Replacement for Sennheiser BA300 Headphone Batteries Lifetime Warranty Capacity: 150mAh, Upstart Battery Brand On Sale for a Limited Time!