The St. Andrew knot is essentially a “convenience” knot with a little bulk to it.It ties quickly, though not as quickly as the smallest knots, and is self-releasing, meaning that you can pull on the tail end of the knot to undo the whole thing. Because the knot is slightly asymmetrical, some men prefer the Pratt/Shelby, or the substantially larger Windsor. For its size, however, the St. Andrew is the most convenient option, and remains popular, especially in the United Kingdom.