Laminaria 4mm Medium – Laminaria is a 100% natural cervical dilator made from a sea-grown plant containing no synthetic materials. Safely utilized for over a century, Laminaria provides gentle, gradual dilation. After harvesting, the plant is dehydrated. Once inserted into the cervical canal, Laminaria absorbs liquid, swelling to several times its initial dried diameter, gently dilating the cervix. UOM: 25/BX.