On-Stage Stands Keyboard X Stand Add On Tier  

Pretty clever design and very sturdy.  The small cross arm that connects the two vertical members helps tie everything together and nice and tight.  Should work well with any type of stand that has hollow round tubes for the upper keyboard support arms.

Fits well in my X stand, and is easy to set up.   I like the adjustible cross-bar making it easy to switch the entire stand set (X and 2nd tier), from a lower (bench play) position to a higher (standing play) position.  To do that I remove the keyboards, loosen the cams, loosen the cross-bar adjustment wheel-screw and then adjust the entire (X and 2nd tier) up or down, then tighten everything and put the keyboards back on.  

Good quality, I use it with my heavy duty On-Stage X stand, which I also recommend.  There are cheep X-stands for the bottom,  but not that much cheaper, come on it's holding your baby, so pay the little $20 more and go for the quality..

Great for the money

I use it at home, and at the gig.   It lets me fit two of my keyboards in the same footprint, which is great for small gigs, where I only have one small space to set up.  

The add on stand was perfect for what I needed and was easy to intall.

The add on stand is very sturdy!

By purchasing the add on stand, it saved me the price of a new stand which may have cost me three to four times more.

One thing that may help is the possibility of creating an add on stand just like this one but with the flexibility to increase the height.