What is this fitting?

STEVE PAUL_3

My son's co-op apartment in Brooklyn had a major re-modeling done 5 years back. The fitting shown in the attachment was used as the washing machine drain standpipe trap, inside the wall. I cannot identify it. I have not been on the site to see it. Does anyone recognise it? what are the tapping sizes? I suspect that this is some sort of a heating fitting that was jury rigged to be used as a trap. The number 9A makes me think Burnham cast Iron baseboard. Any ideas?

Danny Scully

Drum Trap

Thats an old drum type trap, it is not a heating fitting. They're common on old washing machine waste connections.