The 4 models of outdoor APs we sell today are the MR70, 78, 76, 86.
The MR70/78 are basically outdoor versions of the entry level indoor MR20/28.
The MR76 is basically an outdoor MR36 with various external antenna options.
The MR86 would be roughly equivalent to the indoor MR46 again with various external antenna options.
The entire AP family datasheet can help with all the info you need
Where does the MR72 fit into the Picture? MR32? There really needs to be better documentation for this, instead of just saying "Go check the datasheet"
The datasheet has enough information about the products, you just need to be more patient and persistent.
I bet most people in the community learned it by reading the documentation.