Need New ACER CMOS Battery-Pls help-Urgent

Hello
i bought laptop from some1.There was something wrong with CMOS battery so he removed it.Now i need to install new battery.I tried searching for battery on eBay but i did not find any for my laptop.My laptop is Acer TravelMate 4011WLCI.
My question is will it work if i put any other acer CMOS battery.There is some battery on eBay which is for acer. Is all Laptop CMOS battery same.Pls help me.thank you very much in advance