The stretchy Neoprene headband is adjustable thanks to its Velcro. The headband material is very soft and comfortable on the little heads and it’s easy to clean with warm soapy water. The wraparound design and the internal frame made in silicon perfectly keep the glasses over the child’s eyes and guarantee protection against the sun, the wind, the sand and insects. The polycarbonate frame is virtually shatterproof and stand up to wear and tear. The lightweight polarized ophthalmic polycarbonate lenses are virtually shatterproof and scratch resistant. 100% UV 400 (maximum protection). Sunglasses are replaceable and are capable of being cold fitted with a prescription lens -8 to +8. The frame is free from metal parts and screws