I think all the Jaspers stands already come with these holders, so their function should be no mystery.
My only gripe is the little hooks on the end - they are generally fine, but not quite long enough for certain keyboards. For example, the Akai AX60 has an angled lower chassis, so the hooks do not quite come up high enough to hold the keyboard in place. I own a few other vintage keyboards with a similar slope on the bottom, but I haven't tried them yet. I think the Korg DW series and Poly-800 may have similar trouble.
I was able to correct this by replacing the hooks with 1/4 x 3/4 inch aluminum bar stock. I cut the bar to about 65 mm in length, then drilled and countersunk a hole for the screw, and finally spray painted the pieces black. It was a lot of work, but it fixed the problem.
I'm rating these holders 5 stars for stability and quality, but only 4 total because they are not suitable for all keyboards, and Jaspers does not offer longer hooks for the end of the holders.
