I want to buy this battery: http://www.usbphoneworld.com/hp-dv4-ev12.html The original HP one is this: http://www.shopping.hp.com/webapp/shopping/product_detail.do?hpweb_printable=true&product_code=KS526AA&orderflow=1&storeName=accessories&landing=computer&catLevel=1&tab=reviews&subcat1=notebook_batteries&category=categories So as you can see the price difference is huge.