Although I'm reviewing this 0.25mm derma roller, the link seems to go to a derma pen for some reason. I've bought derma rollers in the past for my alopecia. This derma roller seems to have nice, sturdy needles that are just the right length to "wake up" my hair shaft and get the blood moving to stimulate hair growth. So far, with a combination of a couple other things suggested by my dermatologist, I am able to regrow, albeit at a slow pace, my hair in the crown area. My hair growth is slow and I understand it won't happen overnight, but I am patient and with the help of this derma roller, I expect the positive results to continue! Again, I am not reviewing the Hair Pen that this page is connected to. I am strictly reviewing the 0.25mm derma roller that was sent to me via the Vine Program. I'll update as necessary but so far, this derma roller (not the pen) is helping me a lot!