Thanks for the reply. Do you know about the sv6500r tower amt? That is the most likely pair from rbh I'm looking at with the sv661cr in the center. Although I haven't ruled out the 831 yet.\nI've been poking around the rbh website for some months now, seems a little weird the photos show the old amt. Maybe I'm missing something?\nThe SV6500R AMT will be square like the SV61R\/661R AMT.\n\nOnly the SV831\/821 retain the 4.72”x1” AMT.\n\nAs for the website, they are just behind on updating it.