Winstone Aggregates is New Zealand's largest manufacturer and distributor of aggregates and sand to roading, ready mixed concrete, and concrete product industries, and other building and civil engineering customers. The company operates quarries and manufacturing plants throughout the North Island, and in Christchurch in the South. A wide range of durable, high grade concrete aggregates are produced for purposes such as construction and roading. Various specialised aggregates are produced for horticultural, agricultural, landscaping, drainage, and other applications.