Slider 1: Has adjustable legs so the height can be altered. Can be used freestanding or attached to a tripod. The slider carriage moves smoothly and can be used with a tripod head or by attaching a camera directly to it.
Slider 2: The slider carriage is a bit stiff but I think it could be repaired/adjusted. One of the arms is missing but it still works without it on the flat or on a tripod.
Both these are original Glidetrack products.
I don't mind selling these separately if you want to make an offer for one of them but not the other.