Fat Gripz work by instantly convert barbells, dumbbells, chin-up bars and exercise machines handles into THICK BARS. Thick Bars (and Fat Gripz) work for many reasons including:

• Increased muscle activation - thicker handles stimulate much more muscle activation in the hands, forearms and biceps. This increased muscle activation leads to greater muscle and strength gains especially in the arms.
• "Unlocking" muscle gains - thick bars make your hands, fingers and forearms so much stronger that your body can finally stop "holding back" the strength and muscle gains in your uppers arms, back and chest.
• Complete training - thick bar training automatically trains your hands, fingers and forearms at all angles. If you are bench pressing, the thick bar will train your hands and forearms in a completely different way than if you are doing chin ups on a thick bar.
• Natural movement - thick bars perfectly replicate the natural function of the human hand - lifting heavy, awkward objects.
• Automatic training - thick bars means you are training your grip the whole time and you don't even need to do any extra exercises.
• Concentration - thick bars are harder to handle so you need to concentrate a lot harder to lift the weight. Some credit this alone with making them significantly stronger.
• Less imbalances and injuries - thick bars shift the stress off the joints and onto the muscles because a thick bar spreads the weight over a larger area.

Fat Gripz come in three sizes: Fat Gripz Pro 2.25" / 5.7cm outer diameter (the most popular, if in doubt start here), Fat Gripz One 1.75" / 4.5cm outer diameter and Fat Gripz Extreme 2.75" / 7cm outer diameter.