.155 inch-288.7 lb round trimmer line Note: The length of trimmer line should not be too long, and 10 cm to 15 cm should be suitable. The trimmer line too long to pruning weeds and control. And if the trimmer line too long, it breaks easily. The length of the two sides of the trimmer line should be the same, otherwise the lawn mower would flutter because of the unbalance of the trimmer line. If you have any question about the products, just tell us, we will answer for you ASAP.