Loctite 4204 prism is a medium viscosity, thermally resistant, clear, one-part, room temperature cure, rubber toughened OEM assembly instant adhesive. Excellent hot strength and heat aging properties. Adhesive for fiber optic components. Loctite 4204 is a general purpose adhesive suitable for applications where heat resistance is required. Loctite 4204 is toughened with elastomers for flexibility, impact resistance and improved resistance to heat and humidity.