The Hayden standard stone mantel kit is part of a collection of four economical mantel kits that include 3-piece adjustable facing and 3-piece bevelled 1" hearth. The legs of each mantel should be positioned on either side of the firebox opening (up to 45.5" wide). The adjustable facing panels will allow firebox opening heights between 27" and 40". Each mantel has variations in color and texture that captures the true essence of natural stone. Because this stone mantel is lightweight, preparation and installation are much easier and much less costly than traditional solid stone mantels. Special wall and floor reinforcement is not necessary for easy installation. Each stone mantel is fire resistant and allows for zero clearance from combustible material (no space required between firebox and this mantel material or surround facing), making it the perfect choice for gas or wood fireplaces.