parallel bars

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun plural A piece of gymnastic equipment consisting of two horizontal bars, normally set at the same height, on adjustable supports and used mainly for swinging maneuvers.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun gymnastics A set of apparatus consisting of two horizontal bars at a small distance apart, used by male gymnasts, upon which acts of swinging and holding and jumping are performed.
• noun gymnastics A gymnastics event using the parallel bars.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun gymnastic apparatus consisting of two parallel wooden rods supported on uprights