The MD Building Products 5/8 in. x 20 ft. Gray caulk backer rod for gaps and joints acts as a filler in large gaps before applying caulk. It insulates as well as cushions. Use in pavement cracks, wall joints and foundations. Backer rod is easily trimmed to size with scissors.
- Non-absorbent, closed-cell polyethylene pre-caulking material
- Easily trimmed to size with scissors
- Twist multiple strands of cord together for extra large gaps