You are looking at a pack of 20 slot together style railway fencing. 1.4metres in total.
This item is freestanding but definitely advise glueing the panels in place when in its final resting place.
These don't clip in place in the slots they merely butt up in the hole as pictured.
Multi buy if you want more than 1 set.
Dimensions:
70mm long X 31.3mm height x 3.2mm width