Usage Tips:Material: ABS spool and nylon thread, flexible and long service life; These kind of material can reduce drag and achieve fast cutting Save Working Time-easy to use and install pre-wound Tool-less installment, pops in and out of trimmer for ease of use,long lasting saves you time and energy User Precautions: Strong centrifugal force and cutting fast during using, recommend to wear eye protection and long pants to avoid unnecessary injury. And this cordless weed eater parts refill is only suitable for tender weed grass. Strong weeds been recommended to use to trim. spool line is 27 ft/ 8. in length and 0.0629 inch/ 1.6mm in diameter Color: Black Material: ABS, Nylon Package Contents: 1 x replacement spools 1 x trimmer replacement spool cap covers Only the above package content, other products are not included. Note: Light reflection 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.