All Jones H-Bars use a 31.8mm stem clamp diameter, 22.2mm clamp size for controls (standard mountain bike style). The entire front loop has a 22.2mm diameter.
The cross bar on the Loop H-Bar sweeps forward to allow the levers to go behind the cross bar instead of in front. This gives longer uninterrupted hand positions and will allow trigger and grip/twist shifters to fit on the rearward extensions (unlike the original H-bar). The continuous front loop of the bar enhances stiffness and is good for additional aero hand positions and mounting lights, GPS devices etc. This bar provides comfort and power with an impressive weight. With the levers in the optimum position you get a wide range of hand and body positions, from fully upright at the ends of the grips, to a tucked aero position when resting your forearms across the crossbar and loop. In between these extremes, there are many unique and useful positions, making this a true multi-position bar because you'll actually find yourself using all of the positions! The rearward extensions allow extra leverage and a wider hand position - be it for comfort or power. All H-bars are for a 31.8 stem and the crossbar is now tapered and butted with a 31.8 mm clamp area. The grip tubes on the aluminum version are also butted for strength and weight savings. All H-Bars have a standard 22.2mm diameter grip area.
Try wrapping the crossbar with bartape! You can wrap both the crossbar and loop (but it helps to leave a gap in the center of the loop to mount whatever gadgets you have), if you want to have the most hand positions!