It requires some effort to install these. In our balcony, we have a pipeline on the ceiling which was serving as a good meeting point for pigeons. I installed it on the pipeline using scotch tape and it was one tedious job to do; balancing on the ladder and putting tape around the pipe through the gaps between spikes. Had it an option of some double sided tape with it, I guess that wouldn't have been so tedious.
But note that, it still is not effective against small sized birds, sparrows. In fact the sparrows play around on the spikes. Anyway, that's not as much a menace as pigeons were, so I am happy with it.