A caulk gun is a tool used to apply caulk, a flexible material that seals gaps and cracks in various surfaces. It typically consists of a metal or plastic frame with a trigger mechanism that pushes a tube of caulk forward when squeezed. This allows for precise application in areas like windows, doors, and plumbing fixtures. Using a caulk gun is straightforward. First, you insert a tube of caulk into the gun and cut the nozzle to the desired size. Then, you simply squeeze the trigger to dispense the caulk evenly, ensuring a tight seal that helps prevent air and water leaks.