Sizing a spoke wrench correctly matters more than most people think. A loose-fitting wrench rounds off nipple flats in a hurry, and once the flats are gone, you're looking at a spoke replacement instead of a quick truing job. Park Tool's SW-3 is precision-sized for 3.96mm (0.156") wrench flats, which is the 105 gauge nipple size you'll find on select Shimano wheels, hub-drive e-bikes, and heavy-duty wheelsets with heavier gauge spokes. If you've measured your nipple flats with calipers and landed on 3.96mm, this is the wrench you need.

The SW-3 is heat treated and nickel plated for long service, so the engagement surfaces stay crisp over years of use rather than wearing into a sloppy fit. The blue vinyl dip serves two purposes: it gives you grip and tactile feedback when you're working in tight spoke gaps, and it color-codes the wrench so you can grab the right size out of a drawer without checking markings. Park Tool assigns each spoke wrench size its own color, which makes organization straightforward if you keep multiple sizes on hand.

One thing worth noting: spoke gauge and nipple size are not correlated. You can't look at a spoke and assume which wrench you need. The only reliable way to identify the right SW wrench is to measure across the nipple flats with a caliper and match that measurement to the wrench size. If you're between sizes, use the smallest wrench that fits. The SW-3 is made in the USA and has been part of Park Tool's lineup for over 50 years, so this is a known quantity in shops everywhere.