Felting needles are designed to entangle the fibres by pushing and pulling each individual fibre. To do this they have a series of barbs along the working edge that grab the fibres and move them around. They do not break the fibres just entangle them.They are produced in different thickness gauges, the thicker the needle the bigger the barbs. Also the thicker the needle the hole left by it is bigger. This hole does tend to close up as the work relaxes. But for fine work a fine needle is needed. 36 gaugeis considered to be the general working needle. Good for getting the work started.