USE Aero Extensions are compatible with the vast majority of handlebars on the market. External diameter is 22.2mm and they are available in 20°, 30°, 40°, and 50° bends in the Ski-Bend design. Available in both alloy and carbon fibre.
If you want to achieve a high hand position then the 30°, 40° and 50° options are available in a High-Rise option where the shifter cable holes are at the correct end. Available in a carbon fibre only.