Did you get this off the compressor or the condensing unit?
I hope your took it off the compressor.
A basic definition of an air handling unit (AHU) might be “a box with a fan, coils, and filters.” From there it gets considerably more complicated. Proper selection of an air handler requires answering myriad questions ranging from “what capabilities are required?” to “will it fit?” Only after establishing these basic project constraints can the art of evaluating and selecting an AHU begin.
Before starting this process, it’s important to realize that there will not be a “perfect” selection for any AHU as many competing criteria, not the least being cost, will force compromises. It is the engineer’s job to balance and prioritize all of the decisions related to performance, efficiency, maintainability, and space constraints to select a unit that has the lowest lifecycle cost for a given application.