100% stainless steel bird spikes¿¿is made of all 304 stainless steel material, including base bar. The all metal construction assured it is corrosion and weather resistant. Different from bird spikes on polycarbonate bar, the base bar is unclear and more durable which rejects any sunlight and ensure a 10 years warranty. Besides, stainless steel base also has holes for screwing into any surface which is not suitable for glue.