M-D Building ProductsVersatile Gray Foam Backer Rod - Set 5/8in x 20ft - Essential Caulk Saver for Sealing Concrete Gaps, Expansion Joints, and Crack Filling (71506)

I ended up ordering the wrong size for my project and had to return. However, the backer rod seems to be made of high-quality foam, and it feels dense and durable. It has a nice, consistent texture that should be great for filling gaps and joints. I can't speak to how well it works in the long term, but it appears sturdy and like it would do the job as intended.While I didn't end up using the backer rod, Amazon's return service made the process incredibly easy and the refund was instant.

I actually had to buy this in order to post by Doberman puppies cropped ears. This stuff is very easy to use and works wonderfully for this process. It’s easy to cut with just any kitchen scissors and obviously customize it for your needs. It has been very helpful in the process of keeping my puppies ears up straight. And I didn’t have to go to a bunch a stores to find it and have plenty of extra for any other projects I might do.

Very effective for covering gaps. Covers up easily.

Great product used it to put down in my tack room when I put a wood floor down. Worked perfect to keep the boards in place and still have them the expansion gap they needed!

Seals large gaps and saves sealants.

Really Nice. Extremely well made. Great product. Great Shipping. Great price.

Worked well!

I use these for multiple purposes and found they are strong and don't breakdown over time.