All States Ag Parts Muffler Extender Kit - 3.625" I.D. John Deere 4640 4430 4630 4440 R66690 Fits John Deere Tractor(s) 4430, 4440, 4630, 4640 Replaces John Deere OEM nos R66690 Fits factory oem muffler I.D.: 3-5/8" Length: 18"