Plumber's putty is a type of sealing compound used primarily in plumbing applications. It is a soft, pliable material made from a mixture of clay and other substances, which allows it to create a watertight seal around fixtures like sinks, faucets, and drains. This putty is easy to mold and can be applied by hand, making it a popular choice for both professionals and DIY enthusiasts. Once applied, plumber's putty remains flexible, allowing for slight movement without cracking or breaking the seal. It is important to note that while it is effective for sealing, it is not suitable for use with certain materials, such as marble or granite, as it can cause staining.