18" Replaceable Sprocket Nose Bar / Silver Streak R2501872-11041SSPack Size:1GB ET18-50MH, Oregon 180GLGK041Echo CS400, 440, 510, 520, 3600, 3700, 3900, 4000, 4010, 4100, 4200, 4400, 4500, 4510, 4600, 4601, 5000, 5100; Red Max G415AVSPitch: .325", Drive Links: 72, Gauge: .050, Length: 18 ", Type: Replaceable Sprocket Nose