The design is an outer bowl with an inner, removable colander or strainer basket. It is sometimes also called a pasta strainer or kitchen sieve. A tea infuser or a tea strainer may be used to assist in this process. The actual initial drain part in a lavatory or sink is termed a "strainer". It is a perforated metal conical strainer with much larger holes than a chinois. After steeping, the tea is poured into cups through a strainer. However any other filter/strainer may be used to filter the tea. Some teapots have a strainer built-in on the inner edge of the spout. Cast-iron teapots often come with a tea strainer that fits inside. The duplex strainer system usually consists of two separate strainer baskets housings. Snare tension is controlled with a screw on the strainer. The initial pipe that leads from the strainer to the trap is termed the "tailpiece". It usually has a dome strainer in the bottom to prevent splash-back. This eliminates the need for manual cleaning of the strainer element. The rice puffs up and is separated from the sand by a strainer.