A basin wrench isn't used to remove a basin at all. It's used to remove those impossible to reach shallow nuts located on the underside of the sink and that hold the faucet to the sink. The faucet nuts are located behind and at the top of the sink bowl and are impossible to reach without this special tool.
The basin wrench has a long handle with swivel mounted, spring loaded serrated jaw for use with metal nuts. The swivel allows the jaw to rotate 90° and reach the metal faucet nuts which fasten the faucet to an installed sink.
The movable jaw usually open wide enough for nuts about one inch in diameter. The tools swivel mounted jaw can pivot 180° allowing it to flip over, a nice feature as it allows you to turn it clockwise or counter-clockwise to tighten or loosen the nut.
Some variations of this tool include a telescoping handle that allows you to adjust the length for convenience or to gain more leverage.



