as reported in other recessions, there are two versions of the battery NPFW50, a weighing approximately 40gr weight (made in China) and with 50gr (made in Japan). In my Sony Alpha 7R the original battery (made in Japan) was 50gr difficult, the battery in connection with this charger weighs about 40gr. With the Sony Alpha 7R also the China Battery worked perfectly. The trouble is that when ordering is not clear whether this is a China or Japan product.
