Flare Cap Nut is ideal for use with gas, oil, air, and water in the plumbing and heating sectors. This work with steel, brass, copper, and aluminium tubing. Flare fittings can be taken apart and put back together numerous times without affecting the seal. The ideal tool to use to tighten or loosen hexagonal nuts and fittings is a flare-nut wrench. It is therefore adaptable and valuable, particularly when working on plumbing or automobiles.