Professional Grade; 1 Bushing - Silentbloc Forged at high temperatures, the syntheric material used in Raybestos Bushings are built to withstand high-force impacts and extreme weather conditions and won't crack, harden, become brittle or discolor with age. RAYBESTOS Warranty Information RAYBESTOS CHASSIS Professional Grade -24 months/24,000miles. Service Grade - 12 months / 12,000 miles Warranty Details