The EZ bar curl is a popular bicep exercise that targets the upper arms, particularly the biceps and forearms. 

The unique shape of the EZ bar allows for a more natural wrist position, reducing strain on the joints compared to straight barbell curls. 

This makes it a great option for those looking to build arm strength and muscle definition while minimizing discomfort. 

The exercise helps to isolate the biceps, promoting growth and improving overall arm strength.