jmbiii3, the battery number for your Nook HD is BNA-B0002. the battery appears to be available [http://www.amazon.com/Battery2go-Rechargeable-Battery-AVPB001-A110-01-BNA-B002/dp/B00KG6P8QY|right here] and [http://www.amazon.com/Battery2go-Battery-BNA-B002-BNTV250A-AVPB003-A110-01/dp/B00K3X6OG8|here as well]. Of course, always check with the vendor. If you are truly fixed on the 4000mAh you can check [http://translate.google.com/translate?hl=en&sl=auto&tl=en&u=http%3A%2F%2Fitem.taobao.com%2Fitem.htm%3Fid%3D37859845568|on here]