As defined by ASTM F1346, Performance Specification for Safety Covers and labeling Requirements for All Covers for Swimming Pools, Spas and Hot Tubs, a barrier (intended to be completely removed before entry of users), for swimming pools, spas, hot tubs or wading pools, attendant appurtenance and/or anchoring mechanisms which will – when properly labeled, installed, used and maintained in accordance with the manufacturer’s published instructions – reduce the risk of drowning of children under five years of age by inhibiting their access to the contained body of water, and by providing for the removal of any substantially hazardous level of collected surface water. These covers may be power or manual.