I have researched this to the ninth degree - "ditch molding" is the proper term for this molding. Assembly methods use to necessitate this molding due to a seam (result of manufacturing technique common at one time, hence been changed for most manufacturers). 3M engineer and I conversed. I have the width, length and depth measurements secured. Replacement molding is available by the foot/roll. And while not an OEM part, it is a viable alternative to a bad ditch molding or even no molding. This 3M ditch molding has adhesive (peel and tape) on it's backside. Obviously the roof area where you install this molding must be clean of dirt and debris for the ditch molding to adhere.