That I know of there is a OEM Standard 1850 MAH battery. There is the one I have that is a 2100 MAH battery and I do believe there is a 3800 MAH battery. I'm not sure if the 38 is oem but I know the 21 is. Price range but I know the 3800 runs between 60 and 75 bucks... Hope that helps a lil bit.