Unused items found at home. I am selling them as I have no use for them. Brand new, unused. Purchased in early October 2025. Retail price: 5,600 yen Brand: FYBOK Product Name: Compatible with Fujitsu FPB0338S FPCBP531 FMVNBP248 (3490mAh 50Wh 14.4V) Replacement for Lifebook T937 T938 T739 U478 U758 U757 U748 E548 E558 The following is quoted from the product page: Model Number: FPB0338S FPCBP531 FMVNBP248 Voltage: 14.4V Capacity: 3490mAh 50Wh Compatible Models: T937 T938 T739 U478 U758 U757 U748 E548 E558 Please remove the original battery and check the model number on the battery to ensure it matches. A safety inspection is performed before shipment, and the performance, lifespan, and safety meet the needs of your daily work and entertainment. You can use your laptop for extended periods in places without a power outlet. Usage Notes: When using the battery for the first time, discharge it to 20% and then fully charge it, repeating this several times to fully activate the new battery. The battery should always be used, and even if not used for a long time, charge it in a timely manner and keep the battery level above 30% to prolong the battery life. The product meets Japan's unique high safety standards (PSE). Complete protection functions: Overcurrent protection, overcharge protection, over-discharge protection, short circuit protection, and other functions.