Silicone. Soothes and calms baby better (Based on Market Research, June 2013, tested with 110 Nuk pacifier users). BPA free. 100% baby approved orthodontic shape. Unique Nuk Orthodontic Shape: Nuk pacifiers feature a truly orthodontic nipple, which fits baby's mouth better with its unique curved top and scooped bottom shape. This unique design offers room for the tongue to move and supports the natural development of jaw and teeth. 1. True orthodontic shape nipple - naturally fits baby's mouth. 2. Integrated channels - less palate pressure. 3. Scoop nipple cavity - maximizes tongue movement. 4. Heart-shaped shield - prevents irritation. Nuk-USA.com. Made in USA.