So what is a Tricep bar - also known as a hammer curl bar? It's a specialist piece of gym equipment. It's an oval shaped bar that typically has two parallel hand placements that run through its middle and weight shafts on each end. Even though it is called a tricep bar, you can use it to work other body parts besides the triceps.
Similar to the EZ curl bar, you can use it to work the muscles from different angles and it can reduce the stress that a straight barbell can place on the joints in the arm (the wrists, elbows and forearms) by allowing for a much more ergonomic grip of the bar.
Why? Ultimately, this will minimise the chances of injury (keeping in mind that you must have good form as well). Simple huh? What do you use them for? French curls, skull crushers, bicep hammer curls and more.
Run hammer curl exercises through your fave search engine to get a better idea. These are a great utility bar to have around - once you've started using one, it's hard to go back. I say, if you've got the cash, grab one. They come in both standard size (25-28mm shafts) and Olympic size (50mm rotating shafts).
FYI: for anyone not sure, the triceps are the large muscles located on the back of the upper arm. They are principally responsible in life for straightening your arm (extending the elbow joint).
In weight training, they are secondary mucscles in all bench pressing exercises. They can trained using isolation or compound exercises - the hammer curl bar uses isolation exercises. And of course training them does add extra width to the guns...).