Race Loose Exhaust Packing. RFX Race series exhaust packing is the perfect replacement for both 2T and 4T exhaust that have lost packing and become loud. The loose fibers are woven together in long strands and are easy to fit in any silencer. RFX Exhaust packing is suitable up to temperatures of 700 degrees C. Features: High-performance woven fiberglass packing. Manufactured to a high specification for extreme heat resistance. Ideal for reducing sound and rebuilding your exhaust. Universal for 2-stroke and 4-stroke machines. Notes: For best results, do not overfill. Wrap the core snug, but not too tight. The final packing should feel like that of a firm pillow. If the core is wrapped too tight, it will actually increase the noise level.