Wacom Ergo Flex for Cintiq Pro 24 and 32

All of the mounting hardware will be included in the box. The Wacom Ergo Flex for Cintiq Pro 24 and 32 is compatible with Wacom Cintiq Pro 24 (DTK2420, DTH2420) and Wacom Cintiq Pro 32 (DTH3220).

No, the Wacom Ergo Flex for Cintiq Pro 24 and 32 BH #WAACK62803K will not work with the cintiq21ux and there are no adapters available.

This model does come with clamp.

Yes, you can mount it on the side as long as you have space on the sides for it and the desk is thick enough. From Wacom: What are the requirements for a desk to mount the Flex Arm on? The desk plate must have an edge at the back of the desk where the desk clamp can be attached (at least 120mm (4.7in.) wide). It is imperative that the mounting surface is strong enough to support the mounted Flex Arm and Cintiq Pro. For wood-based surfaces, a thickness of 25mm (1in.) or more is recommended.

The ergo stand is a heavy, solid stand. I purchased it with the Cintiq 32. You can only move the display up or down, or angle the display. It's a very stable platform if you don't have space restrictions. I already had the ergo flex so I ended up switching to it as it allows the display to move in infinite directions. I have limited space and this flexibility works well.

Sorry. Only using my desk.

You will need one of these https://bhpho.to/2MvTnGD.

The Wacom Ergo Flex for Cintiq Pro 24 and 32 B&H # WAACK62803K only works with the Cintiq Pro 24 & 32''. It does not work with the older 27'' model. If you have models DTK2700 and DTH2700, you can get the Wacom Cintiq 27QHD Ergo Stand B&H # WAS MFR # ACK411040Z instead.