Neutral grip bars are designed to eliminate the twist in your elbows that occurs with a straight bar.  When your arms hang at your side your grip is near verticle.  These bars are designed to allow a natural grip of 70-90 degrees and take the stress off your joints.  If you have elbow and/or shoulder pain after doing heavy bench this will solve it.  Especially helpful for older lifters.  I am 44 and thought I would have to stop bench press until I switched to these bars.  Fits standard olympic benches and weighs the same as a normal olympic bar.  My first order was taking forever so I bought a second set from another vendor.  Now I have more than I need.  Selling both for $200.