The Simplicity 341231MA Engine Pulley Kit is an authentic OEM replacement part designed to restore optimal engine drive system performance on a range of Simplicity and Snapper riding mowers. This comprehensive kit includes the essential engine pulley, a key for secure shaft attachment, and a bolt for installation. It serves as a direct replacement for several previous part numbers, ensuring compatibility and ease of installation. The pulley features an outer diameter of approximately 139.7 mm (5.5 inches) and a bore diameter of 25.4 mm (1 inch).