Caution! This print could result in harm. Take caution with rubber bands and only load and aim at targets intended to be hit. Depending on how it is printed the rod could be strong and capable of harm to others. Use rubber bands looped together to create the "strings" of the crossbow (once again use caution with rubber bands that can break). There is a groove for the rubber bands to rest in the rod. Adjust sizing as needed. I printed a smaller version and used 3 rubber bands for the "string". It also launches nerf darts.