1/4"-20 UNC threads 0.515" I.D Replacement Number: R26670 Fits John Deere Lawn &Garden Tractor Models: 1010, 2010, 2510, 2520, 4000, 4520, 4320, 3010, 3020, 4010, 5020, 7020, 4020 The throttle control knob of a lawn tractor is a very important part when operating the machine, it allows you to adjust the engine speed according to your needs, thus controlling the speed and efficiency of the tractor Before you start using it, make sure the throttle control knob is in the lowest position, which helps protect the engine and drivetrain During operation, try to avoid abruptly adjusting the throttle control knob to avoid excessive impact on the engine and transmission system When you stop using the tractor, make sure to return the throttle control knob to the lowest position to extend engine time 1/4"-20 UNC threads 0.515" I.D Replacement Number: R26670 Fits John Deere Lawn &Garden Tractor Models: 1010, 2010, 2510, 2520, 4000, 4520, 4320, 3010, 3020, 4010, 5020, 7020, 4020 The throttle control knob of a lawn tractor is a very important part when operating the machine, it allows you to adjust the engine speed according to your needs, thus controlling the speed and efficiency of the tractor Before you start using it, make sure the throttle control knob is in the lowest position, which helps protect the engine and drivetrain During operation, try to avoid abruptly adjusting the throttle control knob to avoid excessive impact on the engine and transmission system When you stop using the tractor, make sure to return the throttle control knob to the lowest position to extend engine time