M-D Building Products - Versatile Gray Foam Backer Rod - Set 5/8in x 150ft - Essential Caulk Saver for Sealing Concrete Gaps, Expansion Joints, and Crack Filling (71552)

Works very well for what I need.

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.

Works great!

Very effective for covering gaps. Covers up easily.

As advertised and affordable. Cuts easy, very flexible, accurate dimensions. Using as backer rod and insulator around patio sliding doors and in driveway. It was nice to find a brand who has a thicker dimension in 5/8 that I needed.

Would buy again. Used for running generator power cord under window in order to seal from cold/hot wind.

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!

Works as advertised, Gray Foam :)

Good

Recommended for purpose and was perfect

Excellent Product ... Works as Intended

Parfait

Worked really well. Used it in a space over an entrance door. Applied caulking over the top with a putty knife. Perfect result.