Unigrass 6600 drawer slides with t-rivet

Hi!
We are looking for drawer slides that have a t-rivet on both ends that fit into a slotted rail (I don't know what this system is called). This is for slide-out shelves inside cabinets. This system makes it easy to adjust the shelves up or down. The sliders are 22 in. in length and we need at least 4 sets of them. These slider have "Unigrass 6600" printed on them, but the ones I find online are missing the rivet to fit in the slots. If you know what this system is called, please let me know. Any help is greatly appreciated!