Uneven bars, also known as asymmetric bars, are an artistic gymnastics apparatus made of a steel frame. The bars themselves are made of fiberglass with wood coating, or less commonly wood. The bars are placed at different heights and widths, allowing the gymnast to transition from bar to bar. The English abbreviation for the event in gymnastics scoring is UB or AB, and the apparatus and event are often referred to simply as "bars". The dimensions of uneven bars used in international gymnastics competitions must conform to the guidelines and specifications set forth by the International Gymnastics Federation Apparatus Norms brochure. Several companies manufacture and sell bars, including AAI in the United States, Jannsen and Fritsen in Europe, and Acromat in Australia.

On the other hand, the high bar, also known as the horizontal bar, is an apparatus used by male gymnasts in artistic gymnastics. It traditionally consists of a cylindrical metal (typically steel) bar that is rigidly held above and parallel to the floor by a system of cables and stiff vertical supports. Current elite-level competition uses a stainless steel core rail. Gymnasts typically wear suede leather grips while performing on the bar.

In summary, uneven bars are made of a steel frame with fiberglass and wood coating, while the high bar is made of a cylindrical metal bar with a stainless steel core rail.