Defines the total number of fine grained item compatibilities that can be applied to a listing.
When you list with parts compatibility, using only the high-level compatibility search names, such as Year, Make, and Model, the fitment applies to the various unspecified lower-level compatibility search names and values, such as Trim and Engine, as well. This means that specifying a single coarsely defined item compatibility may result in multiple fitments applying to the listing at the lowest level of granularity. Up to 300 (or whatever maximum is indicated by MaxItemCompatibility) coarse parts compatibilities can be specified for a given listing.
Alternatively, you can explicitly specify up to 1000 (or whatever maximum is indicated by MaxGranularFitmentCount) parts compatibilities at the lowest level of granularity. That is, if you specify your parts compatibilities using all of the supported compatibility search names (e.g., Year, Make, Model, Trim, and Engine), you can specify up to 1000 compatibilities.
See the Field Index
to learn which calls use MaxGranularFitmentCount.