This foam joint filler backing strip has a diameter of 1/2 in. and is of sufficient length to meet various daily large-scale glue filling and joint sealing requirements. It is made of high-quality foam material, which is safe, environmentally friendly, and has excellent sealing performance. The product is transported in compact packaging for protection, and slight size deviations may occur due to compression. The product has excellent flexibility and can fit various joints. Installation is simple and clean, creating a professional sealing effect. When purchased, a storage spool is provided, making the threading process more convenient. It has a wide range of applications and can be used for joint sealing of various gaps such as door and window joints, wall and wooden surface cracks, sidewalk lane expansion joints, and road joints.