Materials vary: many products use ceramic or stoneware; some kitchen sink strainers are made from rust-resistant plastic; and drain stoppers often include brass and stainless-steel components.
Some drain stoppers and strainers include an internal basket that catches hair, rings, and other debris to help prevent pipe blockages; one listing also describes a brass filter that helps neutralize odors.
Pop-up stoppers are described as using two replaceable rubber seals that form a tight, leak-proof barrier to prevent water from seeping under the sink.
A built-in spring mechanism lets you press the top to toggle between open (drain) and closed (water-retention) positions; the design cites a stainless-steel spring and brass tube for smooth, durable operation.
The stopper is described as compatible with most standard bathroom sinks, installs without special tools, and uses an adjustable rubber seal to accommodate different drain sizes.