World-famous beauty blogger Huda Kattan (a.k.a. Huda Beauty) has more beauty tools in her massive makeup closet than we could ever dream of — including whole sections devoted to scissors, tweezers, and brow products. And yet, not a single one is used in Kattan’s new Instagram post that reveals exactly how she gets flawless brows. Because instead of reaching for stencils, tweezers, tape, or other essential tools, she busts out something used by mechanical engineers: a caliper. We never would have guessed that the utilitarian device, used to measure the distance between two opposite sides of an object, happens to be the blogger’s surprising weapon of choice in achieving the impossible: flawless brows that are identical, not fraternal twins. “My secret to making my brows perfectly symmetrical is using a caliper!” she writes. “I used this when I got started, and it helped so much!” Though taking mechanical gear to your brows may seem strange at first, the video shows that it serves as a spot-on guide for how and where to fill in brows. And because measurements are built into the tool, it prevents overdrawing like a dream. Does holding a caliper to your face look awkward? Sure. But we’re down for anything that helps us inch closer toward brow symmetry.