Have a look at the items page. Items - Planet Mado DBZ RPG
The information displayed for Weighted clothing is wrong. Mostly category based (Light/Medium/Heavy)
Light Weighted Shirt: 6% Bonus to PL gain, -6% Dodge self, +6% Opponents.
Medium Weighted Shirt: 4.5% Bonus to PL gain, -5% Dodge self, +5% Opponents.
Heavy Weighted Shirt: 3% Bonus to PL gain, -3% Dodge self, +3% Opponents.
Looks like they need to be flipped, and then the zenni prices adjusted.