The Cressi Core Vest Base Layer is a 2.5mm neoprene sleeveless vest, designed to be worn under the wetsuit in order to increase the thermal protection of your suit. Whether you are scuba diving, snorkelling, swimming or engaging in any other watersports activity, this extra base layer is perfect for staying warm in cold water, as it is tight fitting to the all-important core, providing that layer of extra protection where it matters most.