Spikes keep birds off a ledge. They do not close a balcony the way a net does. Pick the strip by how long it has to sit outside, then measure the run.
Polycarbonate
The plastic strip is UV polycarbonate. It is the one for ledges, AC outdoor units, signage and parapets, where weight matters and the run is a series of short lengths. Confirm the strip length and the surface it will be fixed to.
SS 304
Stainless 304 is the strip for a rooftop, shed or ledge that should still be there after several seasons. It costs more than the plastic and it is the correct spend when the plastic has already been replaced once.
Monkey spikes are a heavier polycarbonate strip, listed separately. Bird net, in white, green or blue, is what you order when the opening itself has to be closed. Sector 9, Noida. 9910238277.