Wasabi Power Battery for Sigma BP-21 and Sigma SD1, SD1 Merrill, SD14, SD15 Rechargeable lithium-ion battery for Sigma BP-21 Can be charged with the original Sigma charger Premium Japanese cells for longer battery life with no memory effect Rated at 7.4V and increased 2000mAh for 33% longer run time than the Sigma original Includes battery with 3-year manufacturer warranty