M-D Building ProductsVersatile Gray Foam Backer Rod Set 1/2in x 20ft - Essential Caulk Saver for Sealing Concrete Gaps, Expansion Joints, and Crack Filling (71480)

I purchased a home that had never had flexible sealant in the expansion joints. This was perfect to push into the joints before applying sealant. The quality is great and the sealant adhered to it with no problems.

Used this for a hood that was floppy and it looked great. Can't say how good it is for the intended purpose. It's flexible just the right size and stiff enough to make my hood the right shape

Used as filler on gaps in concrete slabs, Effective in use, was of good quality. Purchased on sale at a good discount

easy to use

I was making a ring holder and this was the perfect size, great quality, I didn't care about color it was being covered. Very easy to use....

This works as expected. Fills in gaps well and is easy to cut. Good price. Is flexible and fills large cracks well.

Works well and is flexible, but expensive for what it is.

Amazon wouldn’t post my original positive review due to having the word “crack” in it. This fills cracks awesome. Amazon, do better.