Specification: Material: CNC Aluminum Thread: 4-40#(American Standard) 23 teeth, suitable for all JR series 24 teeth, suitable for all HITEC series 25 teeth, suitable for all FUTABA series Distance from hole center to hole center:1inch, 1.25 inch.1.5inch. 2inch. Multi size for chosing: 1 inch JR 23T 4-40# red 1 inch Hitec 24T 4-40# red 1 inch Futaba 25T 4-40# red 1.25 inch JR 23T 4-40# red 1.25 inch Hitec 24T 4-40# red 1.25 inch Futaba 25T 4-40# red 1.5 inch JR 23T 4-40# red 1.5 inch Hitec 24T 4-40# red 1.5 inch Futaba 25T 4-40# red 2 inch JR 23T 4-40# red 2 inch Hitec 24T 4-40# red 2 inch Futaba 25T 4-40# red Package Included: 1x Servo arms (1.25 inch, 24T )