4-pack, 10ft helix design copolymer nylon resin and synthetic trimmer/edger line Bendable and flexible allowing line to stretch and cushion on impact with surfaces hard Aerodynamic shape allows for less drag for more efficient cuts 100 lbs of tensile strength vs. older lines that only offer 68 lbs of force Spools are suitable for trimmers/edgers from worx series:wg150s,151s,152,155s,165,166 Feature 1.4 x Cordless Grass Trimmer Grass Trimmer Spool Line 2.High quality nylon line, long life flexible and long life 3.A centrifugal force and aerodynamics to reduce drag and achieve fast cutting, save time of tedious manual winding, reduce damage to the trimmer- edges and wont get stuck while mowing. 4. Centrifugal force strong uge and fast cutting when using, recommend wearing eye protection and long pants to avoid unnecessary injury Specification Product name: Line Trimmer Spool Line Material: Nylon Size: Line length 10 feet, diameter 0.065 inch Color: Orange spool with red line, orange cap Compatible trimmer model: WG163, WG163.4, WG163.9, WG160, WG160.4, WG160.3, WG160.1, WG160.2, WG165 WG154, WG155, WG150, WG151, WG151.5, WG151, WG152, WG152, WG155.5, WG156, WG157 WG170, WG175, WG180, WG954, WG921 Compatible Part No: WA0010 Compatible Cap Part No: WA6531 GT Package: 4 x Grass Trimmer Spool Line