SD-NP-BG1 Rechargeable Lithium-Ion Battery - Replacement for Sony NP-BG1 Battery Replacement battery for the Sony NP-BG1, Lithium-Ion (Li-ion) 3.7V (1200mAh) 100% compatible with your OEM battery - 3 year warranty. Made with high quality Japanese cells. Synergy Digital is a Registered Trademark