Durable, flexible tapes with high-quality, long-lasting adhesives prevent movement of air and moisture across seams and joints and are therefore essential for efficient building operation.  Some tapes are specially formulated to be waterproof and yet allow water vapor to pass through them. Others block both liquid water and water vapor.  Thus, some tapes are used for the air/moisture control layer and others for the weather resistant barrier (WRB).  Some tapes can be used for both.