I have JR Sport systems in most of my planes, and they come standard with a 700mAh NiCd pack. These are usually good for 4-5 flights, unless it is on the cold side. On my regular flyer, my Four Star 40, I bought a JR Sport 1500mAh NiMh pack for $19.99 and that pack will fly all day. It is the exact same size and weight as the standard pack.