This is a RRS plate that was not specifically made for ALPA, however fits the frame of the MAX and TC perfectly and has a lip to prevent rotation.
I personally talked with Joe at RRS and he said this plate more than adequate to hold any of the ALPA's and heavier. I used it for 2 years + on my max and and until I sold the TC a few years ago. $68 $29 shipped anywhere in the CONUS.