The 4" FS Square Heavy-Duty Plug from Capitol Manufacturing is designed for secure sealing in piping systems. This plug features a square design, ensuring a tight fit in standard fittings. Made from high-quality materials, it offers exceptional strength and durability, making it suitable for various applications, including water and gas lines. Its design adheres to industry standards, ensuring a reliable and leak-free seal. Ideal for both professional and DIY plumbing projects, this plug is a reliable choice for enhancing your piping infrastructure.