It's this aircraft:
http://www.seatguru.com/airlines/Del..._Version_2.php
The former NW 757 flying across the Atlantic are being moved to the Pacific; these aircraft featured a modified version of the former WBC. It appears DL's adding a pair of rows to these aircraft, so I'm uncertain as to how it would affect the product. In any event, it should be a significant upgrade over standard domestic F (which is more-or-less what was previously used on these flights) and a decent ride for a relatively short flight.