Achieve perfect spoke tension with the Park Tool Master Spoke Wrench. This three-sided spoke wrench is made of heat-treated, polished and plated steel, which maintains robust durability through years of bike maintenance. It's designed to fit in your hands for adeptness while you're adjusting wheel spoke tension. The SW-20 adjusts 0. 136-inch (3. 45 millimeter) spoke nipples, while the SW-20. 2 and SW-20 adjust 0. 127-inch (3. 23 millimeter) spoke nipples.