Andrew Kay & Company Limited, trading as Kays Scotland, is the only remaining UK manufacturer and supplier of curling stones. Founded in 1851, it retains exclusive rights to harvest granite from Ailsa Craig, granted by the Marquess of Ailsa. Kays of Scotland produces the only stones used in competition by the World Curling Federation and is the sole supplier of curling stones to the Winter Olympic Games.

Curling is a sport in which players slide stones on a sheet of ice toward a target area which is segmented into four concentric circles. It is related to bowls, boules, and shuffleboard. Two teams, each with four players, take turns sliding heavy, polished granite stones, also called rocks, across the ice curling sheet toward the house, a circular target marked on the ice. Each team has eight stones, with each player throwing two. The purpose is to accumulate the highest score for a game; points are scored for the stones resting closest to the centre of the house at the conclusion of each end, which is completed when both teams have thrown all of their stones once. A game usually consists of eight or ten ends.