This crossbow is fairly small, however it is extremely powerful for its size, depending on what rubber bands you use. I got a 2x2 lego brick to go 30 feet! The crossbow is only about 8 inches long. It doesn't require many pieces compared to my larger and heavier crossbows. It is also suprisingly accurate as well! 

 

 

 

Interested in building it? Check out the instructable.