Hi Deb, It is styrofoam-just measured it-6 inches around x 4 feet long.I lay on it from back of head on down. You can feel the stretch between your shoulder blades. I have my feet on each side of cylinder and knees in the air. roll from side to side and feel the stretch. I had frozen shoulder BAD following breast surgery to remove tumor in breast and arm pit. Dr. went on vacation and arm swelled up. His partner removed lime green fluid 3 times. (meant infection) as I know now. But it was ignored and not even given anti-biotics. Sent off to rehab specialist and physical therapy -took a year. i did the massage therapy on my own and feel that really helped and also helped desensitization. I still use the foam tool and stretch in others ways dailey. I'm mobile except for one hand. It's crippled, but can use it to type and cut my food. So thankful for that.
You might call physical therapy and ask if they sell them or where you might get one. It's possible sports equipment place might have them. My physical therapy place at the hospital gave it to me to do at home.
Deb, hope the best for you. Let us know how you are doing. your friend, loretta