Description: 【Material】: Crafted from quality PP, these replacement bump head knob boast exceptional wear resistance, making them ideal for high intensity tasks and frequent use in various environments 【Replaces Part Numbers】: Designed to replace models 791-153066B, 791-153066, 791-147153, and 153066. make ensuring a proper fit for your equipment 【Compact Size】: Each knob measures 43*17mm, providing a snug fit while maintaining the functionality of your trimmer without adding unnecessary bulk 【Easy Installation】: The part is quick and easy to install, allowing you to replace the knob without the need for tools 【Value Pack】: Comes as a set of two bump knob assembly, offering value and convenience for replacing simultaneously or keeping a spare on hand Specification: Material: PP Size Chart: 4.3cmx1.7cm/1.69inchx0.67inch Package Includes: 2 Bump Head Knob for String Trimmer Note: Please allow slightly errors 1-2cm/0.39-0.79inch differences due to manual measurement.