Idle speed screw for FCR and FCR MX carburetors. Available part numbers and sizes: - 9.5" (24.2cm): 1034-837-2100 / 021-099 - 13.25" (33.6cm): 1034-837-2501 / 021-531 - 18.90" (48mm): 1034-815-3300 - 18.5cm / 19.5cm: 1034-815-4500 / 021-745 Fitment: Compatible with all FCR and FCR MX carburetors, including: - FCR 28, 31, 33, 35, 37, 39, 41 - FCR MX 33, 37, 38, 39, 40, 41 Note: Parts may vary depending on carburetor type (single, twin, multi, downdraft, horizontal) and vehicle model.Refer to the parts list in the setting manual for accuracy. Compatibility Disclaimer: This is an aftermarket replacement part.Any brand names or model designations mentioned are used solely for the purpose of demonstrating compatibility.