What is a product used to seal, waterproof parts or fill voids?

A sealant is specifically designed to fill gaps and cracks in various materials, providing a barrier against air and moisture. This is essential in construction and maintenance as it helps to prevent water intrusion and damage to structures. Sealants are commonly used around windows, doors, and other openings to ensure that these areas remain watertight and secure against the elements.

The other options serve different purposes that do not align with sealing and waterproofing. Adhesives are mainly used to bond materials together, playing a crucial role in construction and repairs but do not offer waterproofing properties. Fillers are materials used to fill larger voids or imperfections in surfaces but do not provide a waterproof barrier. Coatings often serve to protect surfaces and can offer some level of waterproofing, but they do not function in the same manner as sealants in terms of filling gaps and joints specifically.