thank you for your letter. yes, we take some time to read/charge Japanese' rule is 2.4GHz ISM band. we find that there have a interesting things, that most 2.4GHz chip makers didn't care/consider Japanese rule in and not product as Japanses' asked chips, it means there always just do 2400MHz to 2483.5MHz band chip. so, that seems Japanese manager just set a forbidden to the others, maybe Japanese companies will product the totally legal band 2.4GHz chip for inner use. that is the situation we faced. and seems the Japanese Radio makers, like Futaba and JR,both of them didn't product fully fit Japanese rule's 2.4G radio. that is all.