Bungee is better!

Bungee is superior to metal extension springs for use as springpole.  Metal springs have a low cycle life, usually around 10,000 cycles, which sounds like a lot but not for use as a springpole.  A well conditioned dog can easily do 30 tugs a minute on a spring. This adds up quick and will eventually result in failure, usually when the spring is at full extension which can seriously injure your dog.

Bungee when protected from abrasion and UV rays can be cycled almost indefinitely.  This will give you a long lasting spring and peace of mind for your dogs safety.