for processing: I can - and that is my personal opinion - discover no difference to the original BLM-1.
for compatibility: works only in the E-520 perfect, works with the original charger perfectly, and the most important for me: it works both in the E-5, as well as in battery grip HLD-fourth
to capacity: also no difference to the original. with the battery grip into the E-5 and 2 batteries in it, I had about 2000 pictures (incl. Flash and Live View), the same result I had but also in the use of BLM-1 (from the E-520) and the BLM 5 (from the E-5).
which also was important for me yet: from the E-520 I had the charger for BLM-1, the E-5 charger for BLM. 5 both to similar but not identical design.
However, the Hama-replica has been loaded successfully in both chargers!
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and even a small note in the margin: if people are dissatisfied with a review, but you may comment briefly on what does not fit, so the Rezensionist may consider these comments next time ;-)