This deal has ended.
This Microsoft XBOX 360 Rechargeable Battery 2 Pack drops from $24.99 to $15.99 at Newegg. Plus, the shipping is free. This is the best price we could find on the official Microsoft product by around $3. These batteries work with quick charge and play and charge kits and can last 40 hours per charge. There is no sales tax (except in CA, NJ, TN).