1)
What is "Kidon"?
1.
Radak citing Targum Yonasan: It is a shield.
2.
Radak: It is like a spear, like it says "va'Yischak l'Ra'ash Kidon", "Lahav Chanis v'Chidon" (Iyov 41:21, 39:23).
2)
Why does it say "Aruch k'Ish la'Milchamah"?