[Spool Specifications]: Suitable for Black&Decker Lawnmower Spool, 6.1m 0.15cm, RS-136 / RS-136-BKP / 143684-01. [Compatible Models]: Suitable for Black Decker Lawnmower Trimmers: CST500, ST1000, ST3000, ST4000, ST4050, ST5000, GE600, ST200, ST300, ST400, CST800 and ST6800. [Professional CNC Winding Wheel]: Suitable for Black Decker spool, cut and wound by CNC machine, automatic line change. Manual winding is troublesome and easy to jam during use, causing damage to your lawnmower. [Sturdy Materials]: High quality ABS spool and strong polyamide nylon line, flexible and durable. Use centrifugal force and aerodynamics to reduce drag and enable fast pruning. Precautions: When using this product, take precautions to prevent damage to the machine from loose wires. This product is only suitable for seedlings. For strong seedlings, use other tools, such as pruning shears.