The only kind of bungee cords I've used are the kind with a bundle of rubber strands under a braided cover. The end hooks are crimped over the whole assembly if metal, molded on if plastic. They're pretty good when new, but lose elasticity quickly and are dead after a few years.

I've seen, but not used, the black solid rubber bungees with no cover. The ends of the cords have molded-in holes with metal hooks installed.

How do the solid rubber bungees compare with the braid-covered strands? Is initial elasticity about the same? Is service life any longer?