A triangle racks the balls tight and square, which is what makes a break spread properly — a loose rack absorbs the energy instead of transferring it through the pack.

Timber triangles are the traditional choice and hold their shape well, giving a firm, precise rack every time. PVC triangles are lighter, easy to clean and kinder to the cloth, which makes them popular for home and club tables. The 15-ball triangle is the standard for casino pool and Kelly pool, and is what most tables need.

It is worth replacing a triangle that has lost its square. A rack that does not pull the balls tight is a break that never quite works, and it is one of the cheapest things on a table to put right.