Home Ryobi RY401015US 21. Right Knob For Height Adjustment – 538937002 21. Right Knob For Height Adjustment – 538937002$1.54 21. Right Knob For Height Adjustment - 538937002 quantity Add to cart Buy with Add to wishlist Category: Ryobi RY401015US Description Right Knob For Height Adjustment – Part#538937002 Related products 72. Power Head Led Assembly – 318032001 $28.10 Ryobi RY401015US Add to cart 49. Screw 10 – 14 X 3/4 – 660629005 $1.54 Ryobi RY401015US Add to cart 71. PCBA Controller For Blade – 285001002 $126.20 Ryobi RY401015US Add to cart 70. Plastic; Wire Harness Cover – 542614001 $1.54 Ryobi RY401015US Add to cart