In total I have 16 Mic systems units between frequencies B and C, but unfortunately it is impossible to get those frequencies in places in America, because they are "forbidden"; and although there are some units left in my country, they are not the newest and cost about twice as much. I never thought that in a German company, I was not only going to find what I needed, but completely new units, and it was SO SIMPLE and fast that they sent it to me in Central America... Now, I can rest assured that the original investment I will not have to change it completely, and I can continue using it for a long time, updating components...