This Base Layer can be worn as both an outer and inner layer! Wear it on its own while surfing and swimming in temperate waters, or wear it underneath a wetsuit in colder temperatures as an ideal inner layer.Features:1.3 mm high-stretch Yamamoto 39cell neopreneSCS coating to reduce resistance and friction in the waterMaximum flexibility with an underarm panel, allowing for great freedom of movement, whether worn by itself or under a wetsuitNylon inner lining: makes it easy to get on/off and is more comfortable against the skinA long body length with a special gripper hem panel helps to keep water out of the base layer and so increases warmth