M-D Building Products 20 ft Foam Large 71506 Backer Rod for Gaps and Joints, 5/8-by-20 Feet, Gray, Black, 5/8" x 20'

Recommended for purpose and was perfect

Works very well for what I need.

I use 5/8’s for posting my Dobermans ears and the closest Home Depot was of out of stock so I ordered this from Amazon. This is definitely the wrong size. Much smaller and created issues.

Good

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.

Not every store carries it so it was very convenient to have it delivered to my home next day from Amazon. Price was competitive and exactly what I needed