Seakindly - one off means the mold is good for one time only. *You generally break the mold apart removing the finished product after the layup of gelcoat and fiberglass. *My project boat is a 20ft Seacraft Master Angler that was beat to hell. *This piece is the splashwell that fits against the transom and under the deck. *The person who had "redone" the boat before removed the liner and the splashwell. *I was able to recreate the well (with some modifications) usings pics and taking some painful measurements. *