Eyebrow hairs do not grow in the same type of follicular units as scalp hair. Rather than growing in groups of one to four hairs, they are simply single strands of hair. You can see this if you look carefully in the mirror at your eyebrows. Hair transplant methods have to take this fact into account. There are sebaceous glands in the follicular unit which produce oil. The follicular unit is a living unit with muscle, nerves and blood vessels that are all tiny enough to fit into this small package. The unit is set off by a band of collagen that holds it together. If you look under a microscope at a scalp, you can see follicular units growing in just this way. Repair work is also done at a per graft price. This includes taking out hair plugs from past hair transplant procedures gone wrong. The price may be around $12 per graft when other grafts are being put in at the same time. If the plugs are just being removed, the price is higher, about $15 per graft. They began with a method that was somewhat flawed. While they did use their idea about moving hair from the sides and back of the head to the balding areas, they did not have pleasing results. These hair transplant procedures in the 1960s and 1970s used a method where 15-25 hairs were grafted in a round plug pattern. These new micro grafts are only possible because skilled surgeons have refined the methods of extracting them. Micro grafts are useful in hair transplant surgery because they can give the hair a quite natural appearance. The hair emerges from the scalp in the most natural way, with the same number of hairs that nature intended. They will show you pictures that are not true examples of their own work. They might show you photos that they have taken using lighting tricks to make the hair look thicker and healthier than it is. It is often hard to spot such tricks, but knowing that some surgeons do them will help you to watch out for them.