A&I SCALP RULERNo more mistake an easy way to draw straight lines. These rulers will help you create the best hairline on your customer scalp. These rulers come in set of 4 per box. These ruler come in the 2 options of shape and size to create the recommended hairline. 2 rulers are in round shape hairline and each ruler comes in a 13 scalp line and a second in a 14 scalp line. The 2 others are to design a pointy hairline and also come in a 13 and 14 scalp line