These silicone shields come in three different sizes (small, medium and large). The size you use will depend on the length of your clients lashes as well as their desired look. Small: For a client with shorter lashes, or for a client that would like a more dramatic lift. Medium: For a client that has medium to long lashes or or someone who wants nice balance of lift and curl. Large: For a client that has longer lashes or for someone who wants their lift to have a very natural end result.