Only last 1/3 as long as authentic Sennheiser
I've been using these a few weeks now. They only last about 1.5 hours, whereas my real Sennheiser batteries last nearly 5 hours. These are cheaper but who cares? What's completely unforgivable is that the seller makes it look like you are buying real Sennheiser. Never again. Make sure you are buying Sennheiser - and of course pay the $20 price.