If you have our 25304 professional brake tubing flaring tool, you can already easily produce 45-degree flares. But add this flare die kit and you'll also be able to create the 37-degree flares used in many custom, hydraulic and military applications where an- or jib-type fittings are used. It's a "must have" accessory for custom plumbing and line-fitting on your street rod or hot rod.