Closed-Cell Foam Backer Rod.

Estimated Product Details

Based on standard visual scaling against the zip tie and background textures, this appears to be a standard 1/2-inch diameter roll.

• Estimated Length: ~20 to 25 feet (a partial leftover coil from a standard 100-foot commercial retail pack, or a pre-cut hardware store length). THE LENGTH IS APPROXIMATE-- this product has been used

What It Is Used For

• The Main Job: It is inserted into deep gaps, cracks, or expansion joints (in concrete, masonry, window frames, or decks) before applying caulk or sealant.

• The "Why": It stops you from wasting an entire $15 tube of caulk on a single deep crack. By filling the bottom of the void, it ensures the caulk forms a perfect, flexible "hourglass" shape that expands and contracts without tearing.

• Bonus Uses: People frequently use it as DIY weatherstripping, craft padding, or for keeping couch cushions from sliding out of place.