The Rubber Backer Rod is perfect for a wide range of sealing applications, including door, window, cracks on wall, furniture, machine, and automotive projects. It effectively fills gaps and joints, preventing the infiltration of air, water, and dust, ensuring a tight and long-lasting seal. It can also be used for craft DIY, flower art, etc.SpecificationColor: BlackMaterial: NBR rubberOuter Diameter: 4 mm / 4/32 InchTotal Length: 20 m / 65.6 FeetPackage List: 1 Pcs Backer RodAdvantageThe Backer rod is made of Rubber material that provides good flexibility and heat-resistant features. It is also lightweight and easy to install, making it a good solution for sealing gaps and joints.InstructionSimply insert it into gaps and joints to create a firm and stable foundation for sealants.