This Dinkydoodle Airbrush Pen Replacement Needle Kit is perfect for replacing a damaged needle in your existing Dinkydoodle airbrush. The needle is the most crucial part of your airbrush pen and any damage to it will result in your airbrush not working correctly. If you drop your airbrush pen or it takes a hard knock, this may bend or damage the needle. You may not be able to see any damage but there might be, which means you will need to replace your needle. If you have bent or broken your needle, they are very easy to replace. Simply unscrew the back of your airbrush pen, loosen the cone-shaped nut and pull out the damaged needle. Insert your new needle carefully and slowly push until it is all the way in, then tighten the nut and screw the back of your airbrush pen on. This kit contains three different sized needle tips: 3mm, 4mm and 5mm.