Kunai Knife is a hand-held metal dagger. It has a leaf-shaped blade, handle, and a ring at the end. It is a multiple use weapon that can also be used as a throwing knife. It is one of the most commmon ninja weapns used in the series.
Many ninja have different types of kunai's, and some carry more than one type like Tenten. The most common type of kunai is the basic one, looking like a leaf-shaped blade with a ring end and wrapped handle. However, a more explosive version that is also semi-common is the kunai with the exploding tag. This type of kunai is designed not to directly be thrown at the enemy, but near the enemy, and following a few seconds after it's thrown, it will explode, the intensity of the explosion however varies.
There have also been kunai's shown with a variety of physical differences. Some, are much larger than normal, like thosed used by Prajna Group. Then there are Zabuza's that are slightly curved inward, to have a more deadly affect while thrusting and stabbing. Also, a double-bladed kunai was seen in the Chunin Exam's, used by Team Oboro against Team 7.