Realistically, I think a plaster cast is heavier and more uncomfortable. A fiberglass cast (which is used much more often) would be lighter though. At least with the cast boot though, you can take it off for bathing.
You really should discuss these concerns with your doctor
Posted By Vivian Abrams DPM on August 08, 2005 at 10:42:38:
This slip-on device is a soft and stretchable Nylon/Lycra® fabric molded with a proprietary gel pad to protect the entire Achilles tendon of the foot by absorbing pressure and friction resulted from rubbing with the surface of the shoe.