Amazon.com: Replacement Part NO.753-08122,Gear case/Gearbox Assembly Short Fits for CC350, CC370, CUB Cadet MTD String Trimmer : Patio, Lawn & Garden
MTD Genuine Factory Parts SpeedLock Fixed Line Conversion Kit for 2-Stroke 25 cc Troy-Bilt, Craftsman and Bolens Trimmers with Small Bump Heads 49MSLOCK953 - The Home Depot
MTD TB57 Electric Straight Shaft String Trimmer, Reconditioned