There is no substitute for the commercial grade quality Clubbell®. However, until the funds arrive, some people experiment with homemade substitutes.

I cannot endorse anyone's homebrew concoctions for many obvious legal reasons, though I did want to apprise you of one of the forum member's webpage on how to construct a homemade Clubbell® substitute.
http://www.geocities.com/fightraining/klub.html

I do support making Circular Strength Training™ more accessible to people and the 'filled bat' is about the least dangerous (all homemade inventions were/are to some degree) I used before making the Clubbell®.

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