Sticky Bomb Gun

The Sticky Bomb Launcher is a device used by Batman to shoot small, timed sticky bombs.

The Dark Knight
While in Hong Kong, Batman used the launcher to plant sticky bombs on the side of Lau's building. He noticably set the countdown time to 2:30. The bombs worked effectively and Batman was able to escape with Lau.

Later, Batman used

the bombs while encountering a SWAT Team, who had mistakenly targetted hostages, assuming they were the Joker's men.