Balazs Boxing Unfilled Heavy Bag with Double End - 300 lb.
All Balazs unfilled heavy bags are made from 18 oz vinyl-coated nylon canvas. They are an excellent choice for people who want to minimize shipping charges. Each bag comes complete with a chain assembly, including a twist-free swivel. Bags are double-end compatible. See here
for shock cord assemblies. Available in 25-400 pound bags. The bag can be filled with bits of rag or other soft material and small bags of sand for added weight. Prefilled bags are hydraulically stuffed, so you will not be able to achieve this if you fill the bag by hand.