We offers this heavy duty commercial die-cast aluminum head for the work at hand. Easy line changes, no disassembly or tools required. That means no running back to the garage. These heads work with all of these sizes of line: .080", .095", .130", .155". Mounts using one adaptor and the trimmer's blade bolt or nutNOTE: Use .155" line on straight-shaft trimmers with engines 31cc and larger.Head comes with 16" of .130" trimmer line.