Two seperate devices that fire TNT blocks. The precision cannon fires one TNT block at a time. It goes strait forward. This cannon can cover up to 28 blocks forward. The dual cannon fires two TNT blocks at a time. Instead of going strait, they go forward in a V-shape. This cannon can cover up to 80 blocks forward. The two sources I used for helping me get an idea on how to make these cannons are darkthero (youtube account) and the minecraft battleship server. Darkthero showed how to make a cannon-sized device, and the server showed me how to switch from levers to buttons. The rest is my own twist. I hope you all approve.