CLARKE | Basin Wrench 11 inch Knurled Hook with Swivel Handle | BW11CLxWxH : 30x11. 5x5 centimeters Clarke Basin Wrench are used for tightening tap or 'back' nuts on basins that are not easily accessible with other tools. Our basin wrench features a swivel handle, knurled hook for position grip and reversible direction operation. For tightening tap or 'back' nuts on basins. Not easily accessible with other tools. Swivel handle. Knurled hook for position grip. Reversible direction operation.