The Jackhammer is a Medium Tackle lure with 12" sized skirt saddles. The head shape is a reverse tapered scoop nose with deeper reverse taper compared to the frontal taper.
From "Bonze" Fleet on the Jackhammer:
"Fish commit suicide over this lure. The baby brother of the Violator and Behemoth it has had a lot to live up to and it has not let the family down. With it’s heavily weighted insert and scalloped face it has just enough wiggle to cause trouble! Skirted Length: 330mm / 13” Hook Size: 9/0 – 10/0 Leader Size: 300lb – 400lb."