Spikes are made from weather resistant polypropylene and can be easily attached to the top of the fence or brick wall with screws, nails, and glue or cable ties. The strips are flexible for curved or uneven surfaces. There is a snap off break point, Our bird spike strips have pre-drilled holes in the base; simply attach the bird spikes to the desired fence and boundary with adhesive (plastic available), double-sided tape, cable ties (supplied), tape, and so on, saving you time and effort while providing maximum protection. So that they can be permanently installed and keep birds away. This our anti climb spikes on the top of perimeter fencing, walls and gates to deter intruders and protect your home and garden.