MD-Building Products Backer Rod For Gaps & Joints, 3/8-in x 20-ft

Poly Foam Caulk Saver acts as a filler in large gaps before applying caulk. Insulates and cushions. Use in pavement cracks, wall joints, and foundations.Fills large gaps and openings to prevent drafts.Twist multiple strands of cord together for extra large gaps; easily trimmed to size with scissors.