3/8in x 100ft Sashco Pre-Caulking Closed Cell Backer Rod

Helps fill in and insulate large caulk joints and allows the caulking to absorb more movement. Caulking adheres to the sides of the joint, not to the backer rod, which allows the caulking to stretch and compress without tearing or pulling away. Made of closed cell poly foam. Color: gray.

• Pre-Caulking Filler Rope, backer rod, Grip Strip – sounds boring, right? All of these products fill your caulking joint so you use less caulk and have a perfectly designed joint that stretches properly day in and day out. Boring? Perhaps, but better than redoing the work if you don't use it. Use in all caulking joints 1/2" deep and 1/4" wide, or larger. Available in a wide variety of sizes and shapes
• Easy to fit - soft and pliable, unlike traditional round backer rod and Grip Strip
• Water resistant - repels water to protect the joint from damage
• Saves money - fills the joint so you use less caulk
• Fully compatible with all substrates and Sashco chinking and caulking products