Perhaps it would be useful to know the context for you wanting to know. A lot of the time with fixed pinboxes, it is just a generic piece made by the frame manufacturer. The pinbox usually isn't identified separately unless its a third-party unit where the trailer assembler wants to tout some special feature like Revolution or Air Ride.
2015 Rockwood Signature UltraLite 8282WS Platinum, GY Marathon LRD, TST 507RV TPMS
2005 GMC 2500HD CCSB D/A, Curt E16, Prodigy P2, Garmin RV760LMT w/BC-20 b/u cam