Based on a heat activated, heat curing layer of adhesive supported on a layer of glass fabric reinforcement. The heavy adhesive layer has a slight surface tack/ adhesion at room temperature. When heat activated (e.g. 170°C/338°F for 30 sec) the adhesive will readily flow, bonding to material in its vicinity. Further heating (e.g. 170°C/338°F for 1 minute) will thermoset the adhesive layer and maximise its bond, the glass fabric reinforcements ensures that RD-660 has an excellent tensile strength.