Wasabi Power Battery for Sigma BP-31 and Sigma DP1, DP1s, DP1x, DP2, DP2s, DP2x Rechargeable lithium-ion battery for Sigma BP-31 Can be charged with the original Sigma charger Premium Japanese cells for longer battery life with no memory effect Rated at 3.7V and 1400mAh for a longer run time than the Sigma original Includes BP31 battery with 3-year manufacturer warranty