MONSTER Indexable Slot Cutter End Mill 
 11-1/4" OAL x 4" LOC x 2-3/8" Dia /shank

this is used and awesome - not sure what brand and looks custom.  

This is full of inserts 50 INSERTS!!!   What. that is nuts.  You get all inserts

  I do not know much about these, but one will work ...

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