Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Not Sennheiser brand as indicated.

I hate being duped. The listing clearly indicates that this is a Sennheiser product but it is not. My original batteries are at least 6 years old by my recollection. One still works like new and the other is going bad so i ordered a replacement. At this point the 6+ year old OE battery is making a solid 4 hrs where the aftermarket replacement is falling a bit short. I have not done a truly scientific test at this point, but it is definitely less.I've taken part of the listing that was in place at the time of my order and posted below:Technical DetailsBrand Name: SennheiserSennheiser recommends this battery for owners of the RS 40, RS 45, RS 60, RS 65, RS 80, RS 85 wireless headphone systems and HDR 45, HDR 65, HDR 85 headphones.