Made from durability, silicone, each gasket measures 4 " long, 2 5 / 8 " wide, with a 1 1 / 2 " hole diameter and 3 1 / 8 " bolt spacing for easy installation and consistent under pressure and temperature changes Ideal for homeowners, professional plumbers, and HVAC technicians maintaining residential or commercial hot water heating systems Use during installation, repair, or routine maintenance of pumps flanges in hot water circulation systems to enhancing efficiency and systems downtime This 5pcs silicones flange gasket ensures reliability sealing to minimize leaks in circulating pumps The included spares allow for quick replacements, reducing maintenance delays and ensuring long term reliability for pumps accessories, Manufacturer: jklymm