There are plenty in the local shops in the fitness section. Surgical tubing was what was used for this for this to begin with. Nike sell it with grips. Everlast sell it. I find that some of it is so lite it does not help much. The heavy duty stuff has a pull of about 30lbs which I find is ok but does not give much to work against. suppose you could put 2 together. The sell them in nice colours too which is what really matters.