Here’s a photo of some military webbing which i recently purchased. Its pretty tough stuff, used to hold cargo onto lorries etc. I wasn’t particularly interested in the webbing itself, more the rings on it. These rings can be used around the forearms to add extra weight for training and help condition the muscles, bones, skin and tendons. They help strengthen the whole arm and fist.
This is a link to The 36th Chamber of Shaolin, arguably one of the greatest kung fu films ever made, certainly up there amongst them anyway. It was made by the Shaw Brothers in 1978. In the opening credits you can see Gordon Liu practicing a version of the Hung Ga form “Tiet Sien Kuen” or “Iron Wire Form” using iron rings.
http://www.youtube.com/watch?v=0lrDdfybFhw