Quick view Rotary Corp Replaces 4137 640 0100 Trimmer Gear Box Rotary Corp brand aftermarket product. Trimmer gear box head Replaces 4137 640 0100. Complete unit with gears.Replaces Replaces models: FR130, FR220, FR350, FR450, FR480, FS36, FS40, FS44, FS80, FS75, FS83, FS85, FS90, FS100. $119.95 $91.89 Add to Cart
