Duffy took 4-33 and was named Player of the Match in his T20 debut for New Zealand against Pakistan at Eden Park this year.
Jacobs been a consistent performer on the domestic circuit and his ability to swing the ball made him a particularly compelling option with a Dukes ball in English conditions, Stead said.
Conways inclusion in the squad still depends on immigration officials allowing him dispensation to return to New Zealand when the tour ends. New Zealands borders are open only to returning citizens or permanent residents and Conways application for permanent residency is still being processed. He met crickets residency standard last year after living in New Zealand for three years.
Allrounder Colin de Grandhomme has been named in the squad but will have to pass a fitness test after undergoing surgery on his right ankle in March. Fast bowler Doug Bracewell, who played the most recent of his 27 tests in 2016, also requires a fitness test after suffering a hip injury while veteran batsman Ross Taylor is recovering from a hamstring strain.
Captain Kane Williamson, allrounder Mitchell Santner and fast bowlers Kyle Jamieson and Trent Boult may miss the first test, depending on commitments in the Indian Premier League.
Kane Williamson (captain), Tom Blundell, Trent Boult, Doug Bracewell, Devon Conway, Colin de Grandhomme, Jacob Duffy, Matt Henry, Kyle Jamieson, Tom Latham, Daryl Mitchell, Henry Nicholls, Ajaz Patel, Rachin Ravindra, Mitchell Santner, Tim Southee, Ross Taylor, Neil Wagner, B.J. Watling, Will Young.
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