Simplest way to measure your nails! There are three different sizing kits available. (Round short, Stiletto short, and Coffin medium.) Choose the kit of your desired shape. Each kit includes 10 different size nails. Please ensure you have no product on your nails when measuring. Once you've learned your size, and place a press on order, please include your sizes in the note section upon checkout. Please convert MM measurement to nail size. 12mm= 5 nail size.