1.Max. Length of single thread spool is 9.14 meters and thread diameter 1.65 mm. 6 pcs thread spools the total length is about 55m, satisfy your long-term use. 2. Replacement line spool suitable for GH400 / GH500 / GH600 / GH900 / GH912 / ST6600 / ST1700 / CST1000 / CST1200 / CST2000 / MTC220 / MTE912 / NST2018 / NST1118 / NST2118 / LST220 / LST300 / LST400/LST420/LST136. 3. Device plugged together easily and works. The grass trimmer spool can be exchanged in just a few simple steps. 4. This trimmer line still contains a spring and a spool cover cap, fully compatible spare part. 5. Inserting and removing the coil is tool-free and uncomplicated. At the same time, damage to the device is avoided and the thread is used optimally.