25-2 Bump Feed Trimmer Head 4002 710 2108 for Stihl FS55 FS55R FS56 FS56RC FS70 FS70R FS80 FS85 FS90 FS90R FS91R FS94R FS100RX FS110 FS111RX FS120 FS130 FS131 FS240, Replaces 4002 710 2191

Works just as good as the OEM at a fraction of the cost. The only slight difference, which doesn’t affect fit, is the bump part sticks out a little further than the OEM, or my OEM original was just that far worn down.Installation is easy, there’s a small hole in the trimmers head (may be hidden and plugged with dirt and grass as in my picture), stick a small screwdriver in that hole, rotate the head by hand until you feel your screw driver catch. Unscrew the plastic head by hand, NOTE: It’s a “reverse thread”, meaning you turn it counter clockwise to loosen, clockwise to tighten. Hand tight is all you need, it tightens itself from the direction of its rotation.There’s a bolt head on the opposite side of the hole, its there so you can shoot some grease into the head. If you’re having to replace the part being reviewed its probably already past time to put some trimmer head grease in there.The couple reviews I read of people complaining this replacement “sticks” need to use a little common sense. The OEM ones could stick sometimes as well, the solution is simple. When you take it apart to wrap more string clean the dirt out of it for one thing. You can also take sand paper and smooth out around the bump mechanism and the inside of the hole on the outer cover, common sense, until it works smooth and freely.