The latest Heng Long RC tank to get the 2.4GHz upgrade is the T3889 German Leopard II A6. The 2.4GHz is so much better with longer range, more control allowing you to turn the sound and smoke on and off from the transmitter, and it allows lots of tanks to be used in the same area at the same time without having to swap crystals. Hopefully Heng Long will be upgrading the rest of the range also to the 2.4GHz system soon: