I purchased 6 sets of (5) - very difficult to align. The holes do not align with most of the edging.  You need to buy a lock nuts (8-32 size) and need plyers.  The edging is of very good quality and posh looking, but disappointed in assembling them together. 
If you buy a set of 1 set of 5, maybe it would be easier to keep them together so that they do not come off.