A simple to build and assemble crossbow. Perfect for terrorizing family, friends, pets and co-workers. Fits in the hand nicely, yet not too big. A springy trigger makes this crossbow a pleasure to use. All parts are printed, except for 2 rubber bands. http://youtu.be/Regy2Y768V4 NOTE: I've updated the Handle_Cover so it's not as tight. Print 1 of each item (Arrow optional). I use Slicer with the following settings: Perimeters = 3 Top/Bottom layers = 2 Layer height = 0.2mm Infill = 30% 2 Rubber bands required. A small one (approx 20mm diameter) for the springy trigger, a larger one (approx 50mm diameter) for the bow. First insert the Firing_Lever with small rubberband into handle, then slide in the Trigger. Confirm mechanism is smooth - trim/sand as necessary (depends on your printer quality). Second, wrap larger rubber band around bow, then attach to handle. Lastly, push the handle_cover over the mechanism. It should be a tight fit which holds itself in place. You're good to go!