1Industrial Design: The bow tattoo ruler with an industrial design ensures accuracy in measuring, allowing you to create symmetrical and beautiful brow shapes with ease. 2Strings: There are inked mapping strings in the storage box, which you can get out the trouble of using multiple accessories without dirty your desktop. 3Replaceable Cotton Thread: The inked thread is replaceable and gentle, which is more hygienic and safe, providing your clients more peace of mind. 4Adjustable: The bow tattoo ruler is adjustable to cater to each client unique face shape and size with the middle screw that can be used repeatedly without losing its shape. 5Easy Installment: The microbalding eyebrow ruler with locking wire device at both ends is easier to install than the traditional bow ruler.