Add further detail to trim and accentuate entryways, doors and windows with the addition of a versatile decorative urethane keystone. The flat keystone is designed for use with the flat moulding style FLT152. The flat keystone becomes a contributing addition to the unique enhancements that you envision, whether you are creating something subtle or bold. The flat keystone is crafted in urethane, a strong polymer material that is also lightweight and easy to work with. The keystone attaches easily and it can be installed with many of our durable adhesives. Urethane keystones are precision-molded and non-porous, which prevents the moisture absorption that can cause peeling, staining and decay.