FITS MODELS - Compatible with for string trimmer models: ST1000, ST3000, ST4000, ST4050, ST4500, ST5000, GE600, ST200, ST300, ST400, CST800, ST6800. Spool model: RS-136 / RS-136-BKP / 143684-01.   SPOOL SPECIFICATION - 20ft 0.065 inches line string trimmer replacement spool compatible with for spools models RS-136 / RS-136-BKP / 143684-01. Length 20 foot trimmer line provides a wider range of mowing area. 0.065 inches diameter wearable line supports fast cutting and longer lifetime.   DURABLE MATERIAL - Premium AFS automatic bump feed spool & durable polyamide nylon string trimmer/edger replacement line, pliable and flexible and long service life. Use centrifugal force and aerodynamics to reduce drag and achieve fast cutting string glitch-free.   CONVENIENT&TIME-SAVING - Snap into place for quick and effortless replace without tools. Professional CNC machine cutting and automatic winding is more time-saving than manual winding, reduces damage for string grass trimmer and not get stuck when mowing.   PRECAUTIONS FOR USE - Wear goggles and long pants when using this product to avoid injury from spilling lines. Unplug tool before changing, installing, or removing accessories. This cordless weed eater parts refill is only suitable for young grasses. Strong weeds use other tools.      Colour: Black   Material: ABS, Nylon      Package Contents:   6 * String Trimmer Spool Line      Only the above package content, other products are not included.   Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.