In the case of production, the 500AT & 550AT were made from the mid-1950's, and discontinued in the early 1980's.
As with coverage, they produced 120-125 dB, and covered around 1/2 to 3/4 miles.
Finally, the port ratios were 8 & 12 for single tone, and 8/12, 9/12, & 10/12.