Frost King E/O 3/8 in. Dia x 350 ft. Contractor Pack Caulk Backer Rod C21CP - The Home Depot
M-D 0.5-in x 20-ft Closed Cell Backer Rod, Gray in the Concrete Expansion Joints department at Lowes.com
Amazon.com: M-D Building Products 71480 1/2-Inch by 20-Feet Backer Rod, Gray : Industrial & Scientific
Backer Rod | Polyethylene Foam | Dificonsa
FILL-RITE Backer Rod Closed Cell (2" x 35") - Grey - 8 Pack – FoamNoodles
Foam Backer Rod - Polar Bear Products
EPE Foam Backer Rod, Thickness: 6 Mm at Rs 0.96/meter in Mumbai | ID: 21403130448
1/2" Diameter x 100' Length Backer Rod Caulk Saver Foam Backer Rod for Gaps and Joints Backing Rod Concrete Filler: Amazon.com: Industrial & Scientific